Release 2 (9.2)
Part Number A96584-01
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| Oracle Call Interface Programmer's Guide Release 2 (9.2) Part Number A96584-01 |
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The concepts of binding and defining were introduced and discussed in Chapter 2, "OCI Programming Basics" and in Chapter 5, "Binding and Defining". This chapter provides additional information necessary for users who are developing object applications. The following topics are covered in this chapter:
The OCI datatype mapping and manipulation functions provide the ability to manipulate instances of predefined Oracle C datatypes. These datatypes are used to represent the attributes of user-defined datatypes, including object types in Oracle.
Each group of functions within the OCI is distinguished by a particular naming convention. The datatype mapping and manipulation functions, for example, can be easily recognized because the function names start with the prefix OCI, followed by the name of a datatype, as in OCIDateFromText() and OCIRawSize(). As will be explained later, the names can be further broken down into function groups that operate on a particular type of data.
Additionally, the predefined Oracle C types on which these functions operate are also distinguished by names which begin with the prefix OCI, as in OCIDate or OCIString.
The datatype mapping and manipulation functions are used when an application needs to manipulate, bind, or define attributes of objects that are stored in an Oracle database, or which have been retrieved by a SQL query. Retrieved objects are stored in the client-side object cache, as was described in Chapter 13, "Object Cache Navigation".
This chapter describes the purpose and structure of each of the datatypes that can be manipulated by the OCI datatype mapping and manipulation functions. It also summarizes the different function groups, and gives lists of available functions and their purposes.
This chapter also provides information about how to use these datatypes in bind and define operations within an OCI application.
These functions are valid only when an OCI application is running in object mode. For information about initializing the OCI in object mode, and creating an OCI application that accesses and manipulates objects, refer to the section "Initializing Environment and Object Cache".
| See Also:
For detailed information about object types, attributes, and collection datatypes, refer to Oracle9i Database Concepts. |
Oracle provides a rich set of predefined datatypes with which you can create tables and specify user-defined datatypes (including object types). Object types extend the functionality of Oracle by allowing you to create datatypes that precisely model the types of data with which they work. This can provide increased efficiency and ease-of-use for programmers who are accessing the data.
NCHAR and NVARCHAR2 can be used as attributes in objects and map to OCIString * in C.
Database tables and object types are based upon the datatypes supplied by Oracle. These tables and types are created with SQL statements and stored using a specific set of Oracle internal datatypes, like VARCHAR2 or NUMBER. For example, the following SQL statements create a user-defined address datatype and an object table to store instances of that type:
CREATE TYPE address AS OBJECT (street1 varchar2(50), street2 varchar2(50), city varchar2(30), state char(2), zip number(5)); CREATE TABLE address_table OF address;
The new address type could also be used to create a regular table with an object column:
CREATE TABLE employees (name varchar2(30), birthday date, home_addr address);
An OCI application can manipulate information in the name and birthday columns of the employees table using straightforward bind and define operations in association with SQL statements. Accessing information stored as attributes of objects requires some extra steps.
The OCI application first needs a way to represent the objects in a C-language format. This is accomplished by using the Object Type Translator (OTT) to generate C struct representations of user-defined types. The elements of these structs have datatypes that represent C language mappings of Oracle datatypes.
| See Also:
Table 14-1, "Object Datatype Mappings for Object Type Attributes" for the available Oracle types you can use as object attribute types and their C mappings |
An additional C type, OCIInd, is used to represent null indicator information corresponding to attributes of object types.
| See Also:
For more information and examples regarding the use of the OTT, refer to Chapter 14, "The Object Type Translator (OTT)". |
Oracle followed a distinct design philosophy when specifying the mappings of Oracle predefined types. The current system has the following benefits and advantages:
SELECT ... FROM DUAL" statement. In later releases, this is accomplished by invoking the OCINumber*() functions.In an OCI application, the manipulation of data may be as simple as adding together two integer variables and storing the result in a third variable:
int int_1, int_2, sum; ... /* some initialization occurs */ ... sum = int_1 + int_2;
The C language provides a set of predefined operations on simple types like integer. However, the C datatypes listed in Table 14-1, "Object Datatype Mappings for Object Type Attributes" are not simple C primitives. Types like OCIString and OCINumber are actually structs with a specific Oracle-defined internal structure. It is not possible to simply add together two OCINumbers and store the value in the third.
The following is not valid:
OCINumber num_1, num_2, sum; ... /* some initialization occurs */ ... sum = num_1 + num_2; /* NOT A VALID OPERATION */
The OCI datatype mapping and manipulation functions are provided to enable you to perform operations on these new datatypes. For example, the above addition of OCINumbers could be accomplished as follows, using the OCINumberAdd() function:
OCINumber num_1, num_2, sum; ... /* some initialization occurs */ ... OCINumberAdd(errhp, &num_1, &num_2, &sum): /* errhp is error handle */
The OCI provides functions to operate on each of the new datatypes. The names of the functions provide information about the datatype on which they operate. The first three letters, OCI, indicate that the function is part of the OCI. The next part of the name indicates the datatype on which the function operates. The following table shows the various function prefixes, along with example function names and the datatype on which those functions operate:
The structure of each of the datatypes is described later in this chapter, along with a list of the functions that manipulate that type.
Oracle numbers have a precision of 38 decimal digits. All Oracle number operations are accurate to the full precision, with the following exceptions:
The Oracle date format is mapped in C by the OCIDate type, which is an opaque C struct. Elements of the struct represent the year, month, day, hour, minute, and second of the date. The specific elements can be set and retrieved using the appropriate OCI functions.
The OCIDate datatype can be bound or defined directly using the external typecode SQLT_ODT in the bind or define call.
The OCI date manipulation functions are listed in the following tables, which are organized according to functionality. Unless otherwise specified, the term date in these tables refers to a value of type OCIDate.
| See Also:
The prototypes and descriptions for all the functions are provided in Chapter 18, "OCI Datatype Mapping and Manipulation Functions". |
The following functions perform date conversion.
| Function | Purpose |
|---|---|
|
|
convert date to string |
|
|
convert text string to date |
|
|
convert date from one time zone to another |
The following functions retrieve and assign date elements.
The following functions perform date arithmetic and comparison.
| Function | Purpose |
|---|---|
|
|
add days |
|
|
add months |
|
|
compare dates |
|
|
calculate the number of days between two dates |
The following functions access date information.
| Function | Purpose |
|---|---|
|
|
the last day of the month |
|
|
the first named day after a given date |
|
|
the system date |
The following function checks date validity.
| Function | Purpose |
|---|---|
|
|
check whether a given date is valid |
The following code provides examples of how to manipulate an attribute of type OCIDate using OCI calls. For this example, assume that OCIEnv and OCIError have been initialized as described in Chapter 2, "OCI Programming Basics". See Chapter 13, "Object Cache Navigation" for information about pinning.
#define FMT "DAY, MONTH DD, YYYY" #define LANG "American" struct person { OCIDate start_date; }; typedef struct person person; OCIError *err; person *tim; sword status; /* error status */ uword invalid; OCIDate last_day, next_day; text buf[100], last_day_buf[100], next_day_buf[100]; ub4 buflen = sizeof(buf); /* Pin tim person object in the object cache. */ /* For this example, assume that /* tim is pointing to the pinned object. */ /* set the start date of tim */ OCIDateSetTime(&tim->start_date,8,0,0); OCIDateSetDate(&tim->start_date,1990,10,5) /* check if the date is valid */ if (OCIDateCheck(err, &tim->start_date, &invalid) != OCI_SUCCESS) /* error handling code */ if (invalid) /* error handling code */ /* get the last day of start_date's month */ if (OCIDateLastDay(err, &tim->start_date, &last_day) != OCI_SUCCESS) /* error handling code */ /* get date of next named day */ if (OCIDateNextDay(err, &tim->start_date, "Wednesday", strlen("Wednesday"), &next_day) != OCI_SUCCESS) /* error handling code */ /* convert dates to strings and print the information out */ /* first convert the date itself*/ buflen = sizeof(buf); if (OCIDateToText(err, &tim->start_date, FMT, sizeof(FMT)-1, LANG, sizeof(LANG)-1, &buflen, buf) != OCI_SUCCESS) /* error handling code */ /* now the last day of the month */ buflen = sizeof(last_day_buf); if (OCIDateToText(err, &last_day, FMT, sizeof(FMT)-1, LANG, sizeof(LANG)-1, &buflen, last_day_buf) != OCI_SUCCESS) /* error handling code */ /* now the first Wednesday after this date */ buflen = sizeof(next_day_out); if (OCIDateToText(err, &next_day, FMT, sizeof(FMT)-1, LANG, sizeof(LANG)-1, &buflen, next_day_buf) != OCI_SUCCESS) /* error handling code */ /* print out the info */ printf("For: %s\n", buf); printf("The last day of the month is: %s\n", last_day_buf); printf("The next Wednesday is: %s\n", next_day_buf);
The output will be:
For: Monday, May 13, 1996 The last day of the month is: Friday, May 31 The next Wednesday is: Wednesday, May 15
The OCIDateTime datatype is an opaque structure used to represent Oracle time and timestamp datatypes (TIME, TIME WITH TIME ZONE, TIMESTAMP, TIMESTAMP WITH TIME ZONE) and the ANSI DATE datatype. You can set or retrieve the data in these types (that is, year, day, fractional second) using the appropriate OCI functions.
The OCIInterval datatype is also an opaque structure and is used to represent Oracle interval datatypes (INTERVAL YEAR TO MONTH, INTERVAL DAY TO SECOND).
You can bind and define OCIDateTime and OCIInterval data using the following external typecodes in the bind or define call:
The OCI functions which operate on datetime and interval data are listed in the following tables. More detailed information about these functions can be found in OCI Date, Datetime, and Interval Functions.
In general, functions which operate on OCIDateTime data are also valid for OCIDate data.
The following functions operate on OCIDateTime values. Some of these functions also perform arithmetic operations on datetime and interval values. Some functions may only work for certain datetime types. The possible types are:
DATETIMESTAMPTIMESTAMP WITH TIME ZONETIMESTAMP WITH LOCAL TIME ZONESee the individual function descriptions for more information about input types which are valid for a particular function.
The following snippet of code shows how to use an OCIDateTime datatype to select data from a TIMESTAMP WITH LOCAL TIME ZONE column:
... /* allocate the program variable for storing the data */ OCIDateTime *tstmpltz = (OCIDateTime *)NULL; /* Col1 is a timestamp with local time zone column */ OraText *sqlstmt = (OraText *)"SELECT col1 FROM foo"; /* Allocate the descriptor (storage) for the datatype */ status = OCIDescriptorAlloc(envhp,(dvoid **)&tstmpltz, OCI_DTYPE_TIMESTAMP_LTZ, 0, (dvoid **)0); .... status = OCIStmtPrepare (stmthp, errhp, sqlstmt, (ub4)strlen ((char *)sqlstmt), (ub4)OCI_NTV_SYNTAX, (ub4)OCI_DEFAULT); /* specify the define buffer for col1 */ status = OCIDefineByPos(stmthp, &defnp, errhp, 1, &tstmpltz, sizeof(tstmpltz), SQLT_TIMESTAMP_LTZ, 0, 0, 0, OCI_DEFAULT)); /* Execute and Fetch */ OCIStmtExecute(svchp, stmthp, errhp, 1, 0,(OCISnapshot *) NULL, (OCISnapshot *)NULL, OCI_DEFAULT) At this point tstmpltz contains a valid timestamp with local time zone data. You can get the time zone name of the datetime data using: status = OCIDateTimeGetTimeZoneName(envhp, errhp, tstmpltz, (ub1 *)buf, (ub4 *)buflen); ...
The following functions operate exclusively on interval data. In some cases it is necessary to specify the type of interval involved. Possible types include:
See the individual function descriptions for more detailed information.
| See Also:
Complete lists of the names and purposes as well as more detailed information about these functions can be found in OCI Date, Datetime, and Interval Functions. |
The OCINumber datatype is an opaque structure used to represent Oracle numeric datatypes (NUMBER, FLOAT, DECIMAL, and so forth). You can bind or define this type using the external typecode SQLT_VNU in the bind or define call.
The OCINumber manipulation functions are listed in the following tables, which are organized according to functionality. Unless otherwise specified, the term number in these tables refers to a value of type OCINumber.
| See Also:
The prototypes and descriptions for all the functions are provided in Chapter 18, "OCI Datatype Mapping and Manipulation Functions". |
The following functions perform arithmetic operations.
The following functions perform conversions between numbers and reals, integers, and strings.
The following functions perform exponential and logarithmic operations.
The following functions perform trigonometric operations on numbers.
The following functions perform assign and compare operations on numbers.
The following example shows how to manipulate an attribute of type OCINumber.
struct person { OCINumber sal; }; typedef struct person person; OCIError *err; person* steve; person* scott; person* jason; OCINumber *stevesal; OCINumber *scottsal; OCINumber *debsal; sword status; int inum; double dnum; OCINumber ornum; char buffer[21]; ub4 buflen; sword result; /* For this example, assume OCIEnv and OCIError are initialized. */ /* For this example, assume that steve, scott and jason are pointing to person objects which have been pinned in the object cache. */ stevesal = &steve->sal; scottsal = &scott->sal; debsal = &jason->sal; /* initialize steve's salary to be $12,000 */ inum = 12000; status = OCINumberFromInt(err, &inum, sizeof(inum), OCI_NUMBER_SIGNED, stevesal); if (status != OCI_SUCCESS) /* handle error from OCINumberFromInt */; /* initialize scott's salary to be same as steve */ OCINumberAssign(err, stevesal, scottsal); /* initialize jason's salary to be 20% more than steve's */ dnum = 1.2; status = OCINumberFromReal(err, &dnum, DBL_DIG, &ornum); if (status != OCI_SUCCESS) /* handle error from OCINumberFromReal */; status = OCINumberMul(err, stevesal, &ornum, debsal); if (status != OCI_SUCCESS) /* handle error from OCINumberMul */; /* give scott a 50% raise */ dnum = 1.5; status = OCINumberFromReal(err, &dnum, DBL_DIG, &ornum); if (status != OCI_SUCCESS) /* handle error from OCINumberFromReal */; status = OCINumberMul(err, scottsal, &ornum, scottsal); if (status != OCI_SUCCESS) /* handle error from OCINumberMul */; /* double steve's salary */ status = OCINumberAdd(err, stevesal, stevesal, stevesal); if (status != OCI_SUCCESS) /* handle error from OCINumberAdd */; /* get steve's salary in integer */ status = OCINumberToInt(err, stevesal, sizeof(inum), OCI_NUMBER_SIGNED, &inum); if (status != OCI_SUCCESS) /* handle error from OCINumberToInt */; /* inum is set to 24000 */ /* get jason's salary in double */ status = OCINumberToReal(err, debsal, sizeof(dnum), &dnum); if (status != OCI_SUCCESS) /* handle error from OCINumberToReal */; /* dnum is set to 14400 */ /* print scott's salary as DEM0001`8000.00 */ buflen = sizeof(buffer); status = OCINumberToText(err, scottsal, "C0999G9999D99", 13, "NLS_NUMERIC_CHARACTERS='.`' NLS_ISO_CURRENCY='Germany'", 54, &buflen, buffer); if (status != OCI_SUCCESS) /* handle error from OCINumberToText */; printf("scott's salary = %s\n", buffer); /* compare steve and scott's salaries */ status = OCINumberCmp(err, stevesal, scottsal, &result); if (status != OCI_SUCCESS) /* handle error from OCINumberCmp */; /* result is positive */ /* read jason's new salary from string */ status = OCINumberFromText(err, "48`000.00", 9, "99G999D99", 9, "NLS_NUMERIC_CHARACTERS='.`'", 27, debsal); if (status != OCI_SUCCESS) /* handle error from OCINumberFromText */; /* jason's salary is now 48000.00 */
Fixed or variable-length string data is represented to C programs as an OCIString *.
The length of the string does not include the null character.
For binding and defining variables of type OCIString * use the external typecode SQLT_VST.
| See Also:
The prototypes and descriptions for all the functions are provided in Chapter 18, "OCI Datatype Mapping and Manipulation Functions". |
The following functions allow the C programmer to manipulate an instance of a string.
This example assigns a text string to a string, then gets a pointer to the string part of the string, as well as the string size, and prints it out.
Note the double indirection used in passing the vstring1 parameter in OCIStringAssignText().
OCIEnv *envhp; OCIError *errhp; OCIString *vstring1 = (OCIString *)0; OCIString *vstring2 = (OCIString *)0; text c_string[20]; text *text_ptr; sword status; strcpy(c_string, "hello world"); /* Assign a text string to an OCIString */ status = OCIStringAssignText(envhp, errhp, c_string, (ub4)strlen(c_string),&vstring1); /* Memory for vstring1 is allocated as part of string assignment */ status = OCIStringAssignText(envhp, errhp, "hello again", (ub4)strlen("This is a longer string."),&vstring1); /* vstring1 is automatically resized to store the longer string */ /* Get a pointer to the string part of vstring1 */ text_ptr = OCIStringPtr(envhp, vstring1); /* text_ptr now points to "hello world" */ printf("%s\n", text_ptr);
Variable-length raw data is represented in C using the OCIRaw *datatype.
For binding and defining variables of type OCIRaw *, use the external typecode SQLT_LVB.
| See Also:
The prototypes and descriptions for all the functions are provided in Chapter 18, "OCI Datatype Mapping and Manipulation Functions" |
The following functions perform OCIRaw operations.
In this example, a raw data block is set up and a pointer to its data is obtained.
Note the double indirection in the call to OCIRawAssignBytes().
OCIEnv *envhp; OCIError *errhp; sword status; ub1 data_block[10000]; ub4 data_block_len = 10000; OCIRaw *raw1; ub1 *raw1_pointer; /* Set up the RAW */ /* assume 'data_block' has been initialized */ status = OCIRawAssignBytes(envhp, errhp, data_block, data_block_len, &raw); /* Get a pointer to the data part of the RAW */ raw1_pointer = OCIRawPtr(envhp, raw1);
Oracle provides two types of collections: variable-length arrays (VARRAYs) and nested tables. In C applications, varrays are represented as OCIArray *, and nested tables are represented as OCITable *. Both of these datatypes (along with OCIColl and OCIIter, described later) are opaque structures.
A variety of generic collection functions enable you to manipulate collection data. You can use these functions on both varrays and nested tables. In addition, there is a set of functions specific to nested tables.
You can allocate an instance of a varray or nested table using OCIObjectNew() and free it using OCIObjectFree().
| See Also:
The prototypes and descriptions for all the functions are provided in "OCI Collection and Iterator Functions" |
Oracle provides two types of collections: variable-length arrays (varrays) and nested tables. Both varrays and nested tables can be viewed as sub-types of a generic collection type.
In C, a generic collection is represented as OCIColl *, a varray is represented as OCIArray *, and a nested table as OCITable *. Oracle provides a set of functions to operate on generic collections (such as OCIColl *). These functions start with the prefix OCIColl, as in OCICollGetElem(). The OCIColl*() functions can also be called to operate on varrays and nested tables.
The generic collection functions are grouped into two main categories:
The generic collection functions represent a complete set of functions for manipulating varrays. Additional functions are provided to operate specifically on nested tables. They are identified by the prefix OCITable, as in OCITableExists().
The following generic functions manipulate collection data:
The following generic functions enable you to scan collections with a collection iterator. The iterator is of type OCIIter, and is created by first calling OCIIterCreate().
This example creates and uses a collection iterator to scan through a varray.
OCIEnv *envhp; OCIError *errhp; text *text_ptr; sword status; OCIArray *clients; OCIString *client_elem; OCIIter *iterator; boolean eoc; dvoid *elem; OCIInd *elemind; /* Assume envhp, errhp have been initialized */ /* Assume clients points to a varray */ /* Print the elements of clients */ /* To do this, create an iterator to scan the varray */ status = OCIIterCreate(envhp, errhp, clients, &iterator); /* Get the first element of the clients varray */ printf("Clients' list:\n"); status = OCIIterNext(envhp, errhp, iterator, &elem, (dvoid **) &elemind, &eoc); while (!eoc && (status == OCI_SUCCESS)) { client_elem = *(OCIString)**elem; /* client_elem points to the string */ /* the element pointer type returned by OCIIterNext() through 'elem' is the same as that of OCICollGetElem(). Refer to OCICollGetElem() for details. */ /* client_elem points to an OCIString descriptor, so to print it out, get a pointer to where the text begins */ text_ptr = OCIStringPtr(envhp, client_elem); /* text_ptr now points to the text part of the client OCIString, which is a NULL-terminated string */ printf(" %s\n", text_ptr); status = OCIIterNext(envhp, errhp, iterator, &elem, (dvoid **)&elemind, &eoc); } if (status != OCI_SUCCESS) { /* handle error */ } /* destroy the iterator */ status = OCIIterDelete(envhp, errhp, &iterator);
As its name implies, one table may be nested, or contained within another, as a variable, attribute, parameter or column. Nested tables may have elements deleted, by means of the OCITableDelete() function.
For example, suppose a table is created with 10 elements, and OCITableDelete() is used to delete elements at index 0 through 4 and 9. The first existing element is now element 5, and the last existing element is element 8.
As noted above, the generic collection functions may be used to map to and manipulate nested tables. In addition, the following functions are specific to nested tables. They should not be used on varrays.
When a nested table is fetched into the object cache, its elements are given a transient ordering, numbered from zero to the number of elements, minus 1. For example, a table with 40 elements would be numbered from 0 to 39.
You can use these position ordinals to fetch and assign the values of elements (for example, fetch to element i, or assign to element j, where i and j are valid position ordinals for the given table).
When the table is copied back to the database, its transient ordering is lost. Delete operations may be performed against elements of the table. Delete operations create transient holes; that is, they do not change the position ordinals of the remaining table elements.
You can retrieve a locator to a nested table. A locator is like a handle to a collection value, and it contains information about the database snapshot which exists at the time of retrieval. This snapshot information helps the database retrieve the correct instantiation of a collection value at a later time when collection elements are fetched using the locator.
Unlike a LOB locator, a collection locator cannot be used to modify a collection instance, they merely locate the correct data. Using the locator enables an application to return a handle to a nested table without having to retrieve the entire collection, which may be quite large.
A user specifies when a table is created if a locator should be returned when a collection column or attribute is fetched, using the RETURN AS LOCATOR specification.
| See Also:
Oracle9i SQL Reference for more information |
You can use the OCICollIsLocator() function to determine whether a collection is a locator.
The collection element itself can be directly or indirectly another collection type. Multilevel collection type is the name given to such a top-level collection type.
Multilevel collections have the following characteristics:
OCI routines work with multilevel collections. The following routines can return in parameter *elem a OCIColl*, which can be used in any of the collection routines:
The following functions take a collection element and add it to an existing collection. Parameter elem could be an OCIColl* if the element type is another collection:
Assume that the following types and tables are used for the example:
type_1 (a NUMBER, b NUMBER) NT1 TABLE OF type_1 NT2 TABLE OF NT1
The following snippet of code iterates over the multilevel collection:
... OCIColl *outer_coll; OCIColl *inner_coll; OCIIter *itr1, *itr2; Type_1 *type_1_instance; .... /* assume outer_coll points to a valid coll of type NT2 */ checkerr(OCIIterCreate(envhp, errhp, outer_coll, &itr1)); for(eoc = FALSE;!OCIIterNext(envhp, errhp, itr, (dvoid **) &elem, (dvoid **) &elem_null, &eoc) && !eoc;) { inner_coll = (OCIColl *)elem; /* iterate over inner collection.. */ checkerr(errhp, OCIIterCreate(envhp, errhp, inner_coll, &itr2)); for(eoc2 = FALSE;!OCIIterNext(envhp, errhp, itr2, (dvoid **)&elem2, (dvoid **) &elem2_null, &eoc2) && !eoc2;) { type_1_instance = (Type_1 *)elem2; /* use the fields of type_1_instance */ } /* close iterator over inner collection */ checkerr(errhp, OCIIterDelete(envhp, errhp, &itr2)); } /* close iterator over outer collection */ checkerr(errhp, OCIIterDelete(envhp, errhp, &itr)); ...
A REF (reference) is an identifier to an object. It is an opaque structure that uniquely locates the object. An object may point to another object by way of a REF.
In C applications, the REF is represented by OCIRef *.
| See Also:
The prototypes and descriptions for all the functions are provided in Chapter 18, "OCI Datatype Mapping and Manipulation Functions". |
The following functions perform REF operations.
This example tests two REFs for NULL, compares them for equality, and assigns one REF to another. Note the double indirection in the call to OCIRefAssign().
OCIEnv *envhp; OCIError *errhp; sword status; boolean refs_equal; OCIRef *ref1, *ref2; /* assume refs have been initialized to point to valid objects */ /*Compare two REFs for equality */ refs_equal = OCIRefIsEqual(envhp, ref1, ref2); printf("After first OCIRefIsEqual:\n"); if(refs_equal) printf("REFs equal\n"); else printf("REFs not equal\n"); /*Assign ref1 to ref2 */ status = OCIRefAssign (envhp, errhp, ref1, &ref2); if(status != OCI_SUCCESS) /*error handling*/ /*Compare the two REFs again for equality */ refs_equal = OCIRefIsEqual(envhp, ref1, ref2); printf("After second OCIRefIsEqual:\n"); if(refs_equal) printf("REFs equal\n"); else printf("REFs not equal\n");
When a given type is created with the CREATE TYPE statement, it is stored in the server and associated with a type descriptor object (TDO). In addition, the database stores descriptor objects for each data attribute of the type, each method of the type, each parameter of each method, and the results returned by methods. The following table lists the OCI datatypes associated with each type of descriptor object.
| Information Type | OCI Datatype |
|---|---|
|
Type |
OCIType |
|
Type Attributes Collection Elements Method Parameters Method Results |
OCITypeElem |
|
Method |
OCITypeMethod |
Several OCI functions (including OCIBindObject() and OCIObjectNew()) require a TDO as an input parameter. An application can obtain the TDO by calling OCITypeByName(), which gets the type's TDO in an OCIType variable. Once you obtain the TDO, you can pass it, as necessary to other calls.
These capabilities allow you to model self-descriptive data. You can store heterogeneous data types in the same column and query the type of data in an application.
These definitions are used in the discussion in the following sections:
CREATE TYPE. They are stored persistently in the database.SYS.ANYDATA models such data in SQL or PL/SQL.SYS.ANYDATASET models such data in SQL or PL/SQL.Interfaces are available in both OCI (C language) as well as in SQL and PL/SQL for constructing and manipulating these type descriptions as well as self-descriptive data. The following sections describe the relevant OCI interfaces.
| See Also:
For more information see "Persistent Objects, Transient Objects, and Values", and Oracle9i SQL Reference, section "Oracle-Supplied Types" for an overview |
The type interfaces can be used to construct named as well as anonymous transient object types (structured with attributes) and collection types. The OCITypeBeginCreate() call is used to begin type construction of transient object types as well as collection types (the typecode parameter determines which one is being constructed).
You need to allocate a parameter handle using OCIDescriptorAlloc(). Subsequently, type information (for attributes of an object type as well as for the collection element's type) needs to be set using OCIAttrSet(). For object types, use OCITypeAddAttr() to add the attribute information to the type. After information on the last attribute has been added, you must call OCITypeEndCreate().
For example:
OCITypeBeginCreate( ...) /* Begin Type Creation */ OCIDescriptorAlloc(...) OCIAttrSet(...) OCITypeAddAttr(...) /* Add attribute 1 */ OCIAttrSet(...) OCITypeAddAttr(...) /* Add attribute 2 */ ... OCITypeEndCreate(...) /* End Type Creation */
For collection types, the information on the collection element type needs to be set with OCITypeSetCollection(). Subsequently, OCITypeEndCreate() is called to finish construction.
For example:
OCITypeBeginCreate( ...) /* Begin Type Creation */ OCIDescriptorAlloc(...) OCIAttrSet(...) OCITypeSetCollection(...) /* Set information on collection element etc.*/ OCITypeEndCreate(...) /* End Type Creation */
The OCIDescribeAny() call can be used to obtain the OCIType corresponding to a persistent type.
The OCIDescriptorAlloc() call can be used to allocate an OCIParam (with the parent handle being the environment handle). Subsequently, OCIAttrSet() can be called with the following allowed attribute types to set relevant type information:
To set numeric precision. Pass a (ub1 *) attribute value to the buffer holding precision value.
To set numeric scale. Pass a (sb1 *) attribute value to the buffer holding scale value.
To set the character set id for character types. Pass a (ub2 *) attribute value to the buffer holding char set id.
To set the character set form for character types. Pass a (ub1 *) attribute value to the buffer holding character set form value.
Length of VARCHAR2, RAW, and so on. Pass a (ub4 *) attribute value to the buffer holding length.
To set typecode. Pass a (ub2 *) attribute value to the buffer holding typecode. This attribute needs to be set first.
To set OCIType of an object or collection attribute. Pass a (OCIType *) attribute value to the OCIType corresponding to the attribute. It is your responsibility to make sure that the OCIType is pinned when this OCIParam is used during AnyType construction. If it is a transient type attribute, its allocation duration should be at least as much as the top level OCIType being created. There will be an exception returned otherwise.
OCI_TYPECODE_DATE, OCI_TYPECODE_NUMBER, OCI_TYPECODE_VARCHAR, OCI_TYPECODE_ RAW, OCI_TYPECODE_CHAR, OCI_TYPECODE_VARCHAR2, OCI_TYPECODE_VARCHAR, OCI_TYPECODE_BLOB, OCI_TYPECODE_BFILE, OCI_TYPECODE_CLOB
OCI_TYPECODE_TIMESTAMP, OCI_TYPECODE_TIMESTAMP_TZ, OCI_TYPECODE_TIMESTAMP_LTZ.
OCI_TYPECODE_INTERVAL_YM, OCI_TYPECODE_INTERVAL_DS.
OCI_TYPECODE_OBJECT or OCI_TYPECODE_REF (for REFS) or OCI_TYPECODE_VARRAY or OCI_TYPECODE_TABLE and set the OCI_ATTR_TDO to the OCIType corresponding to the transient type.
The OCIDescribeAny() call can be used to obtain the OCIType corresponding to a persistent type. For example:
OCIDescribeAny(svchp, errhp. (dvoid *)"SCOTT.EMP", (ub4)strlen("SCOTT.EMP"), (ub1)OCI_OTYPE_NAME, (ub1)OCI_DEFAULT, OCI_PTYPE_TYPE, dschp);
From the describe handle (dschp), the OCIType can be obtained using OCIAttrGet() calls.
OCIDescribeAny() can be called with these transient type descriptions for a dynamic description of the type. The OCIType pointer can be passed directly to OCIDescribeAny() (with objtype set to OCI_OTYPE_PTR). This provides a way to obtain attribute information by name as well as position.
For transient types that represent builtin types (created with a builtin typecode), the parameter handle that describes these types (which will be of type OCI_PTYPE_TYPE) will support the following extra attributes.
OCI_ATTR_DATA_SIZE,
OCI_ATTR_TYPECODE,
OCI_ATTR_DATA_TYPE,
OCI_ATTR_PRECISION,
OCI_ATTR_SCALE,
OCI_ATTR_CHARSET_ID
OCI_ATTR_CHARSET_FORM,
OCI_ATTR_LFPRECISION,
OCI_ATTR_FSPRECISION
These attributes will have the usual meanings they have while describing a type attribute.
An OCIAnyData encapsulates type information as well as a data instance of that type (that is, self descriptive data). An OCIAnyData can be created from any builtin or user-defined type instance using the OCIAnyDataConvert() call. This call does a conversion (cast) to an OCIAnyData.
Alternatively, object types and collection types can be constructed piece by piece (an attribute at a time for object types or a collection element at a time). To construct in this fashion, OCIAnyDataBeginCreate() should be called with the type information (OCIType). Subsequently OCIAnyDataAttrSet() can be used for object types and OCIAnyDataCollAddElem() can be used for collection types. OCIAnyDataEndCreate() must then be called to finish the construction process.
Subsequently, the access routines can be invoked. To convert (cast) an OCIAnyData to the corresponding type instance, the OCIAnyDataAccess() call can be used.
An OCIAnyData that is based on an object or collection type can also be accessed piece by piece.
Special collection construction and access calls are provided for performance improvement. These calls can be used to avoid unnecessary creation and copying of the entire collection in memory. For example:
OCIAnyDataConvert(...) /* Cast a builtin or user-defined type instance to an OCIAnyData in 1 call. */ OCIAnyDataBeginCreate(...) /* Begin AnyData Creation */ OCIAnyDataAttrSet(...) /* Attribute-wise construction for object types */
or,
OCIAnyDataCollAddElem(...) /* Element-wise construction for collections */ OCIAnyDataEndCreate(...) /* End OCIAnyData Creation */
The function OCIAnyDataTypeCodeToSqlt() converts the OCITypeCode for an AnyData value to the SQLT code that corresponds to the representation of the value as returned by the OCIAnyData API.
The following typecodes are used in the OCIAnyData functions only:
In calls to other functions, such as OCIDescribeAny(), these typecodes are not returned and you must use the charset form to determine if the data is NCHAR (if charset form is SQLCS_NCHAR).
OCIAnyDataTypeCodeToSqlt() converts OCI_TYPECODE_CHAR as well as OCI_TYPECODE_VARCHAR2 to the output values SQLT_VST (which corresponds to the OCIString mapping) with a charset form of SQLCS_IMPLICIT. OCI_TYPECODE_NVARCHAR2 will also return SQLT_VST (OCIString mapping is used by OCIAnyData API) with a charset form of SQLCS_NCHAR.
| See Also:
For more information see "OCIAnyDataTypeCodeToSqlt()" |
An OCIAnyDataSet encapsulates type information as well as a set of instances of that type. OCIAnyDataSetBeginCreate() is called to begin the construction process. OCIAnyDataSetAddInstance() is called to add a new instance and this call returns the OCIAnyData corresponding to that instance.
Then, the OCIAnyData functions can be invoked to construct this instance. OCIAnyDataSetEndCreate() is called once all instances have been added.
For access, call OCIAnyDataSetGetInstance() to get the OCIAnyData corresponding to the instance. Only sequential access is supported. Subsequently, the OCIAnyData access functions can be invoked.For example:
OCIAnyDataSetBeginCreate(...) /* Begin AnyDataSet Creation */ OCIAnyDataSetAddInstance(...) /* Add a new instance to the AnyDataSet */ /* Use the OCIAnyData*() functions to create the instance */ OCIAnyDataSetEndCreate(...) /* End OCIAnyDataSet Creation */
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Note: For complete descriptions of all the calls in these interfaces, see Chapter 20, "OCI Any Type and Data Functions". |
This section provides information on binding named datatypes, such as objects and collections, and REFs.
For a named datatype (object type or collection) bind, a second bind call is necessary following OCIBindByName(), or OCIBindByPos(). The OCI Bind Object Type call, OCIBindObject(), sets up additional attributes specific to the object type bind. An OCI application uses this call when fetching data from a table which has a column with an object datatype.
The OCIBindObject() call takes, among other parameters, a Type Descriptor Object (TDO) for the named data type. The TDO, of datatype OCIType is created and stored in the database when a named data type is created. It contains information about the type and its attributes. An application can obtain a TDO by calling OCITypeByName().
The OCIBindObject() call also sets up the indicator variable or structure for the named data type bind.
When binding a named data type, use the SQLT_NTY datatype constant to indicate the datatype of program variable being bound. SQLT_NTY indicates that a C struct representing the named data type is being bound. A pointer to this structure is passed to the bind call.
With inheritance and instance substitutability, you can bind a subtype instance where the supertype is expected.
It is possible that working with named data types may require the use of three bind calls in some circumstances. For example, to bind a static array of named data types to a PL/SQL table, three calls must be invoked: OCIBindByName(), OCIBindArrayOfStruct(), and OCIBindObject().
See Also:
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As with named data types, binding REFs is a two-step process. First, call OCIBindByName() or OCIBindByPos(), and then call OCIBindObject().
REFs are bound using the SQLT_REF datatype. When SQLT_REF is used, then the program variable being bound must be of type OCIRef *.
With inheritance and REF substitutability, you can bind a REF value to a subtype instance where a REF to the supertype is expected.
See Also:
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This section presents some additional important information to keep in mind when working with named data type and REF binds. It includes pointers about memory allocation and indicator variable usage.
OCIBindObject() call (dvoid ** indpp) is used, and the scalar indicator is completely ignored.OCIBindObject() is completely ignored.NULL pointer in the indpp parameter for the OCIBindObject() call. During the bind, this means that the object is not atomically NULL and none of its attributes are NULL.indsp, and program variable size pointer, pgvsp, in the OCIBindObject() call is optional. Users can pass NULL if these parameters are not needed.For doing array binds of named data types or REFs, for array inserts or fetches, the user needs to pass in an array of pointers to buffers (preallocated or otherwise) of the appropriate type. Similarly, an array of scalar indicators (for SQLT_REF types) or an array of pointers to indicator structs (for SQLT_NTY types) needs to be passed.
| See Also:
For more information about SQLT_NTY, see the section "New External Datatypes". |
This section provides information on defining named data types (for example, objects, collections) and REFs.
For a named datatype (object type, nested table, varray) define, two define calls are necessary. The application should first call OCIDefineByPos(), specifying SQLT_NTY in the dty parameter. Following OCIDefineByPos(), the application must call OCIDefineObject(). In this case, the data buffer pointer in OCIDefineByPos() is ignored and additional attributes pertaining to a named data type define are set up using the OCI Define Object attributes call, OCIDefineObject().
There SQLT_NTY datatype constant is specified for a named datatype define. In this case, the application fetches the result data into a host-language representation of the named data type. In most cases, this will be a C struct generated by the Object Type Translator.
When making an OCIDefineObject() call, a pointer to the address of the C struct (preallocated or otherwise) must be provided. The object may have been created with OCIObjectNew(), allocated in the cache, or with user-allocated memory.
However, in the presence of inheritance, we strongly recommend using objects in the object cache and not passing objects allocated out of user memory from the stack. The reason is that due to instance substitutability, the server may send back a subtype instance when the client is expecting a supertype instance. This requires the server to dynamically re-size the object -- which is possible only for objects in the cache.
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Note: Please refer to the section"Information for Named Datatype and REF Defines, and PL/SQL OUT Binds" for more important information about defining named data types. |
As with named data types, defining for a REF output variable is a two-step process. The first step is a call to OCIDefineByPos(), and the second is a call to OCIDefineObject(). Also as with named data types, the SQLT_REF datatype constant is passed to the dty parameter of OCIDefineByPos().
SQLT_REF indicates that the application will be fetching the result data into a variable of type OCIRef *. This REF can then be used as part of object pinning and navigation, as described in Chapter 6.
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Note: Please refer to the section"Information for Named Datatype and REF Defines, and PL/SQL OUT Binds" for more important information about defining |
This section presents some additional important information to keep in mind when working with named data type and REF defines. It includes pointers about memory allocation and indicator variable usage.
A PL/SQL OUT bind refers to binding a placeholder to an output variable in a PL/SQL block. Unlike a SQL statement, where output buffers are set up with define calls, in a PL/SQL block, output buffers are set up with bind calls. Refer to the section "Binding Placeholders in PL/SQL" for more information.
OCIDefineObject() call (dvoid ** indpp) is used, and the scalar indicator is completely ignored.OCIDefineObject() is completely ignored.NULL pointer in the indpp parameter for the OCIDefineObject() call. During a fetch or PL/SQL OUT bind, this means that the user is not interested in any information about nullity.OCIObjectNew() call).
For an object define with type SQLT_NTY, client applications wanting to preallocate object memory must use the OCIObjectNew() function. Client applications should not allocate the object in its own private memory space, such as with malloc() or on the stack. The OCIObjectNew() function allocates the object in the object cache. The allocated object can be freed using OCIObjectFree(). Refer to Chapter 17, "OCI Navigational and Type Functions" for details on OCIObjectNew() and OCIObjectFree().
NULL address for the output variable or the indicator, memory for the variable or the indicator will be implicitly allocated by OCI.NULL (in a SQL define or PL/SQL OUT bind), only the NULL indicator struct will get allocated (implicitly if necessary) and populated accordingly to indicate the atomic nullity of the object. The top-level object, itself, will not get implicitly allocated.OCIObjectFree(). If there is a top-level object (as in the case of a non-atomically NULL object), then the indicator is freed when the top-level object is freed with OCIObjectFree(). If the object is atomically null, then there is no top-level object, so the indicator must be freed separately.indsp, and program variable size pointer, pgvsp, in the OCIDefineObject() call is optional. Users can pass NULL if these parameters are not needed.For doing array defines of named data types or REFs, the user needs to pass in an array of pointers to buffers (preallocated or otherwise) of the appropriate type. Similarly, an array of scalar indicators (for SQLT_REF types) or an array of pointers to indicator structs (for SQLT_NTY types) needs to be passed.
Previous chapters of this book have discussed OCI bind and define operations. "What is Binding?" discussed the basics of OCI bind operations, while "What is Defining?" discusses the basics of OCI define operations. Information specific to binding and defining named data types and REFs is found in Chapter 5, "Binding and Defining".
The sections covering basic bind and define functionality showed how an application could use a scalar variable or array of scalars as an input (bind) value in a SQL statement, or as an output (define) buffer for a query.
The sections covering named data types and REFs showed how to bind or define an object or reference. Chapter 10, "OCI Object-Relational Programming" expanded on this to talk about pinning object references, object navigation, and fetching embedded instances.
The purpose of this section is to cover binding and defining of individual attribute values, using the datatype mappings explained in this chapter.
Variables of one of the types defined in this chapter, such as OCINumber or OCIString, can typically be declared in an application and used directly in an OCI bind or define operation as long as the appropriate datatype code is specified. The following table lists the datatypes that can be used for binds and defines, along with their C mapping, and the OCI external datatype which must be specified in the dty (datatype code) parameter of the bind or define call.
The following section presents examples of how to use C-mapped datatypes in an OCI application.
| See Also:
For a discussion of OCI external datatypes, and a list of datatype codes, refer to Chapter 3, "Datatypes". |
The examples in this section demonstrate how variables of type OCINumber can be used in OCI bind and define operations.
Assume, for this example, that the following person object type was created:
CREATE TYPE person AS OBJECT (name varchar2(30), salary number);
This type is then used to create an employees table which has a column of type person.
CREATE TABLE employees (emp_id number, job_title varchar2(30), emp person);
The Object Type Translator (OTT) generates the following C struct and null indicator struct for person:
struct person { OCIString * name; OCINumber salary;}; typedef struct person person; struct person_ind { OCIInd _atomic; OCIInd name; OCIInd salary;} typedef struct person_ind person_ind;
| See Also:
For a complete discussion of OTT, see Chapter 14, "The Object Type Translator (OTT)" |
Assume that the employees table has been populated with values, and an OCI application has declared a person variable:
person *my_person;
and fetched an object into that variable through a SELECT statement, like
text *mystmt = (text *) "SELECT person FROM employees WHERE emp.name='Andrea'";
This would require defining my_person to be the output variable for this statement, using appropriate OCI define calls for named datatypes, as described in the section "Advanced Define Operations". Executing the statement would retrieve the person object named Andrea into the my_person variable.
Once the object is retrieved into my_person, the OCI application now has access to the attributes of my_person, including the name and the salary.
The application could go on to update another employee's salary to be the same as Andrea's, as in
text *updstmt = (text *) "UPDATE employees SET emp.salary = :newsal WHERE emp.name = 'MONGO'";
Andrea's salary (stored in my_person->salary) would be bound to the placeholder :newsal, specifying an external datatype of VARNUM (datatype code=6) in the bind operation:
OCIBindByName(...,":newsal",...,&my_person->salary,...,6,...); OCIStmtExecute(...,updstmt,...);
Executing the statement updates Mongo's salary in the database to be equal to Andrea's, as stored in my_person.
Conversely, the application could update Andrea's salary to be the same as Mongo's, by querying the database for Mongo's salary, and then making the necessary salary assignment:
text *selstmt = (text *) "SELECT emp.salary FROM employees WHERE emp.name = 'MONGO'"; OCINumber mongo_sal; ... OCIDefineByPos(...,1,...,&mongo_sal,...,6,...); OCIStmtExecute(...,selstmt,...); OCINumberAssign(...,&mongo_sal, &my_person->salary);
In this case, the application declares an output variable of type OCINumber and uses it in the define step. In this case we define an output variable for position 1, and use the appropriate datatype code (6 for VARNUM).
The salary value is fetched into the mongo_sal OCINumber, and the appropriate OCI function, OCINumberAssign(), is used to assign the new salary to the copy of the Andrea object currently in the cache. To modify the data in the database, the change must be flushed to the server.
The examples in the previous section should give some idea of the flexibility which the Oracle datatypes provide for bind and define operations. The goal of this section is to show how the same operation can be performed in several different ways. The goal is to give you some idea of the variety of ways in which these datatypes can be used in OCI applications.
The examples in this section are intended to demonstrate the flow of calls used to perform certain OCI tasks. An expanded pseudocode is used for the examples in this section. Actual function names are used, but for the sake of simplicity not all parameters and typecasts are filled in. Additionally, other necessary OCI calls, like handle allocations, have been omitted.
The scenario for these examples is as follows:
BRUCE exists in the employees table for a hospital. See person type and employees table creation statements in the previous section.RADIOLOGIST.RADIOLOGY_CHIEF, and along with the promotion comes a salary increase.salaries, defined as follows:
CREATE TABLE salaries (job_title varchar2(20), salary integer));
Accomplishing the above task requires that the application retrieve the salary corresponding to RADIOLOGY_CHIEF from the salaries table, and update Bruce's salary. A separate step would write his new title and the modified object back to the database.
Assuming that a variable of type person has been declared
person * my_person;
and the object corresponding to Bruce has been fetched into it, the following sections present three different ways in which the salary update could be performed.
This example uses the following method:
#define INT_TYPE 3 /* datatype code for sword integer define */ text *getsal = (text *) "SELECT salary FROM salaries WHERE job_title='RADIOLOGY_CHIEF'"; sword new_sal; OCINumber orl_new_sal; ... OCIDefineByPos(...,1,...,new_sal,...,INT_TYPE,...); /* define int output */ OCIStmtExecute(...,getsal,...); /* get new salary as int */ OCINumberFromInt(...,new_sal,...,&orl_new_sal); /* convert salary to OCINumber */ OCINumberAssign(...,&orl_new_sal, &my_person->salary); /* assign new salary */
This method eliminates one of the steps in Method 1:
#define VARNUM_TYPE 6 /* datatype code for defining VARNUM */ text *getsal = (text *) "SELECT salary FROM salaries WHERE job_title='RADIOLOGY_CHIEF'"; OCINumber orl_new_sal; ... OCIDefineByPos(...,1,...,orl_new_sal,...,VARNUM_TYPE,...); /* define OCINumber output */ OCIStmtExecute(...,getsal,...); /* get new salary as OCINumber */ OCINumberAssign(...,&orl_new_sal, &my_person->salary); /* assign new salary */
This method accomplishes the entire operation with a single define and fetch. No intervening output variable is used, and the value retrieved from the database is fetched directly into the salary attribute of the object stored in the cache.
#define VARNUM_TYPE 6 /* datatype code for defining VARNUM */ text *getsal = (text *) "SELECT salary FROM salaries WHERE job_title='RADIOLOGY_CHIEF'"; ... OCIDefineByPos(...,1,...,&my_person->salary,...,VARNUM_TYPE,...); /* define bruce's salary in cache as output variable */ OCIStmtExecute(...,getsal,...); /* execute and fetch directly */
As the previous three examples show, the C datatypes provide flexibility for binding and defining. In these examples an integer can be fetched, and then converted to an OCINumber for manipulation. An OCINumber can be used as an intermediate variable to store the results of a query. Or, data can be fetched directly into a desired OCINumber attribute of an object.
In the above examples, extra steps would be necessary to insure that changes are written to the database permanently. This may involve SQL UPDATE calls and OCI transaction commit calls.
These examples all dealt with define operations, but a similar situation applies for binding.
Similarly, although these examples dealt exclusively with the OCINumber type, a similar variety of operations are possible for the other Oracle C types described in the remainder of this chapter.
The following code fragments demonstrate the use of SQLT_NTY bind and define calls, including OCIBindObject() and OCIDefineObject(). In each example, a previously defined SQL statement is being processed.
/* ** This example performs a SQL insert statement */ void insert(envhp, svchp, stmthp, errhp, insstmt, nrows) OCIEnv *envhp; OCISvcCtx *svchp; OCIStmt *stmthp; OCIError *errhp; text *insstmt; ub2 nrows; { orttdo *addr_tdo = NULLP(orttdo); address addrs; null_address naddrs; address *addr = &addrs; null_address *naddr = &naddrs; sword custno =300; OCIBind *bnd1p, *bnd2p; ub2 i; /* define the application request */ checkerr(errhp, OCIStmtPrepare(stmthp, errhp, (text *) insstmt, (ub4) strlen((char *)insstmt), (ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT)); /* bind the input variable */ checkerr(errhp, OCIBindByName(stmthp, &bnd1p, errhp, (text *) ":custno", (sb4) -1, (dvoid *) &custno, (sb4) sizeof(sword), SQLT_INT, (dvoid *) 0, (ub2 *)0, (ub2 *)0, (ub4) 0, (ub4 *) 0, (ub4) OCI_DEFAULT)); checkerr(errhp, OCIBindByName(stmthp, &bnd2p, errhp, (text *) ":addr", (sb4) -1, (dvoid *) 0, (sb4) 0, SQLT_NTY, (dvoid *) 0, (ub2 *)0, (ub2 *)0, (ub4) 0, (ub4 *) 0, (ub4) OCI_DEFAULT)); checkerr(errhp, OCITypeByName(envhpx, errhp, svchpx, (const text *) SCHEMA, (ub4) strlen((char *)SCHEMA), (const text *) "ADDRESS_VALUE", (ub4) strlen((char *)"ADDRESS_VALUE"), OCI_DURATION_SESSION, &addr_tdo)); if(!addr_tdo) { printf("Null tdo returned\n"); goto done_insert; } checkerr(errhp, OCIBindObject(bnd2p, errhp, addr_tdo, (dvoid **) &addr, (ub4 *) 0, (dvoid **) &naddr, (ub4 *) 0));
/* ** This example executes a SELECT statement from a table which includes ** an object. */ void selectval(envhp, svchp, stmthp, errhp) OCIEnv *envhp; OCISvcCtx *svchp; OCIStmt *stmthp; OCIError *errhp; { orttdo *addr_tdo = NULLP(orttdo); OCIDefine *defn1p, *defn2p; address *addr = (address *)NULL; sword custno =0; sb4 status; /* define the application request */ checkerr(errhp, OCIStmtPrepare(stmthp, errhp, (text *) selvalstmt, (ub4) strlen((char *)selvalstmt), (ub4) OCI_NTV_SYNTAX, (ub4) OCI_DEFAULT)); /* define the output variable */ checkerr(errhp, OCIDefineByPos(stmthp, &defn1p, errhp, (ub4) 1, (dvoid *) &custno, (sb4) sizeof(sword), SQLT_INT, (dvoid *) 0, (ub2 *)0, (ub2 *)0, (ub4) OCI_DEFAULT)); checkerr(errhp, OCIDefineByPos(stmthp, &defn2p, errhp, (ub4) 2, (dvoid *) 0, (sb4) 0, SQLT_NTY, (dvoid *) 0, (ub2 *)0, (ub2 *)0, (ub4) OCI_DEFAULT)); checkerr(errhp, OCITypeByName(envhpx, errhp, svchpx, (const text *) SCHEMA, (ub4) strlen((char *)SCHEMA), (const text *) "ADDRESS_VALUE", (ub4) strlen((char *)"ADDRESS_VALUE"),OROODTSES, &addr_tdo)); if(!addr_tdo) { printf("NULL tdo returned\n"); goto done_selectval; } checkerr(errhp, OCIDefineObject(defn2p, errhp, addr_tdo, (dvoid **) &addr, (ub4 *) 0, (dvoid **) 0, (ub4 *) 0)); checkerr(errhp, OCIStmtExecute(svchp, stmthp, errhp, (ub4) 1, (ub4) 0, (OCISnapshot *) NULL, (OCISnapshot *) NULL, (ub4) OCI_DEFAULT));
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 Copyright © 1996, 2002 Oracle Corporation. All Rights Reserved. |
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