OCL Function Reference

The following tables list the functions supported by the EDB OCL connector. Note that any and all header files must be supplied by the user. Advanced Server does not supply any such files.

Connect, Authorize and Initialize Functions

Function	Description
OCIBreak	Aborts the specified OCL function.
OCIEnvCreate	Creates an OCL environment.
OCIEnvInit	Initializes an OCL environment handle.
OCIInitialize	Initializes the OCL environment.
OCILogoff	Releases a session.
OCILogon	Creates a logon connection.
OCILogon2	Creates a logon session in various modes.
OCIReset	Resets the current operation/protocol.
OCIServerAttach	Establishes an access path to a data source.
OCIServerDetach	Removes access to a data source.
OCISessionBegin	Creates a user session.
OCISessionEnd	Ends a user session.
OCISessionGet	Gets session from session pool.
OCISessionRelease	Releases a session.
OCITerminate	Detaches from shared memory subsystem.

Using the tnsnames.ora File

The OCIServerAttach and OCILogon method uses NET_SERVICE_NAME as connection descriptor specified in the dblink parameter of the tnsnames.ora file. Use the tnsnames.ora file (compatible with Oracle databases), to specify database connection details. OCL searches the user’s home directory for a file named .tnsnames.ora; if OCL doesn’t find the .tnsnames.ora file in the user’s home directory, it searches the tnsnames.ora on path specified in TNS_ADMIN environment variable.

Multiple descriptors (NET_SERVICE_NAME) can be specified in tnsnames.ora file.

The sample tnsnames.ora file contains:

 EDBX =
(DESCRIPTION =
  (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 5444))
  (CONNECT_DATA = (SERVER = DEDICATED)(SID = edb))
)

Any parameters not included in the files are ignored by the Open Client Library. In the example, SID refers to the database named edb, in the cluster running on the localhost on port 5444.

A C program call to OCIServerAttach that uses the tnsnames.ora file will look like:

static text *username = (text *) "enterprisedb";
static text *password = (text *) "edb";
static text *attach_str = "EDBX";
OCIServerAttach(srvhp, errhp, attach_str, strlen(attach_str), 0);

If you don’t have a tnsnames.ora file, supply the connection string in the form //localhost:5444/edbx.

Note

Multiple Descriptors are also supported in tnsnames.ora.

Handle and Descriptor Functions

Function	Description
OCIAttrGet	Get handle attributes. Advanced server supports the following handle attributes: OCI_ATTR_USERNAME, OCI_ATTR_PASSWORD, OCI_ATTR_SERVER, OCI_ATTR_ENV, OCI_ATTR_SESSION, OCI_ATTR_ROW_COUNT, OCI_ATTR_CHARSET_FORM, OCI_ATTR_CHARSET_ID, EDB_ATTR_STMT_LEVEL_TX, OCI_ATTR_MODULE
OCIAttrSet	Set handle attributes. Advanced server supports the following handle attributes: OCI_ATTR_USERNAME, OCI_ATTR_PASSWORD, OCI_ATTR_SERVER, OCI_ATTR_ENV, OCI_ATTR_SESSION, OCI_ATTR_ROW_COUNT, OCI_ATTR_CHARSET_FORM, OCI_ATTR_CHARSET_ID, EDB_ATTR_STMT_LEVEL_TX, OCI_ATTR_MODULE, OCI_ATTR_PREFETCH_ROWS
OCIDescriptorAlloc	Allocate and initialize a descriptor.
OCIDescriptorFree	Free an allocated descriptor.
OCIHandleAlloc	Allocate and initialize a handle.
OCIHandleFree	Free an allocated handle.
OCIParamGet	Get a parameter descriptor.
OCIParamSet	Set a parameter descriptor.

EDB_ATTR_EMPTY_STRINGS

By default, Advanced Server will treat an empty string as a NULL value. You can use the EDB_ATTR_EMPTY_STRINGS environment attribute to control the behavior of the OCL connector when mapping empty strings. To modify the mapping behavior, use the OCIAttrSet() function to set EDB_ATTR_EMPTY_STRINGS to one of the following:

Value	Description
OCI_DEFAULT	Treat an empty string as a NULL value.
EDB_EMPTY_STRINGS_NULL	Treat an empty string as a NULL value.
EDB_EMPTY_STRINGS_EMPTY	Treat an empty string as a string of zero length.

To find the value of EDB_ATTR_EMPTY_STRINGS, query OCIAttrGet().

EDB_ATTR_HOLDABLE

Advanced Server supports statements that execute as WITH HOLD cursors. The EDB_ATTR_HOLDABLE attribute specifies which statements execute as WITH HOLD cursors. The EDB_ATTR_HOLDABLE attribute can be set to any of the following three values:

• EDB_WITH_HOLD - execute as a WITH HOLD cursor

• EDB_WITHOUT_HOLD - execute using a protocol-level prepared statement

• OCI_DEFAULT - see the definition that follows

You can set the attribute in an OCIStmt handle or an OCIServer handle. When you create an OCIServer handle or an OCIStmt handle, the EDB_ATTR_HOLDABLE attribute for that handle is set to OCI_DEFAULT.

You can change the EDB_ATTR_HOLDABLE attribute for a handle by calling OCIAttrSet() and retrieve the attribute by calling OCIAttrGet().

When Advanced Server executes a SELECT statement, it examines the EDB_ATTR_HOLDABLE attribute in the OCIServer handle. If that attribute is set to EDB_WITH_HOLD, the query is executed as a WITH HOLD cursor.

If the EDB_ATTR_HOLDABLE attribute in the OCIServer handle is set to EDB_WITHOUT_HOLD, the query is executed as a normal prepared statement.

If the EDB_ATTR_HOLDABLE attribute in the OCIServer handle is set to OCI_DEFAULT, Advanced Server uses the value of the EDB_ATTR_HOLDABLE attribute in the OCIServer handle (if the EDB_ATTR_HOLDABLE attribute in the OCIServer is set to EDB_WITH_HOLD, the query executes as a WITH HOLD cursor, otherwise, the query executes as a protocol-prepared statement).

EDB_HOLD_CURSOR_ACTION

The EDB_HOLD_CURSOR_ACTION attribute alters the way WITH HOLD cursors are created using the OCL interface. You can set this attribute to any of the following values:

• EDB_COMMIT_AFTER_CURSOR – commit the transaction after creating the cursor

• EDB_CURSOR_WITHOUT_XACT_BLK – do not begin a new transaction chain

• OCI_DEFAULT - see the definition that follows

The following describes the attribute values.

OCI_DEFAULT

Each time you execute a statement, the OCL examines the transaction state on the database server. If a transaction is not already in progress, the OCL executes a BEGIN statement to create a new transaction block, and then executes the statement that you provide. The transaction block remains open until you call OCITransCommit() or OCITransRollback().

By default, the database server closes any open cursors when you commit or rollback. If you (or the OCL) declare a cursor that includes the WITH HOLD clause, the cursor result set is persisted on the database server, and you may continue to fetch from that cursor. However, the database server will not persist open cursors when you roll back a transaction. If you try to fetch from a cursor after a ROLLBACK, the database server will report an error.

EDB_COMMIT_AFTER_CURSOR

If your application must read from a WITH HOLD cursor after rolling back a transaction, you can arrange for the OCL to commit the transaction immediately after creating the cursor by setting EDB_HOLD_CURSOR_ACTION to EDB_COMMIT_AFTER_CURSOR prior to creating such a cursor. For example:

ub4        action = EDB_COMMIT_AFTER_CURSOR;

OCIAttrSet(stmt, OCI_HTYPE_STMT, &action, sizeof(action),
  EDB_ATTR_HOLD_CURSOR_ACTION, err);

OCIStmtExecute( ... );

It is important to understand that using EDB_COMMIT_AFTER_CURSOR will commit any pending changes.

EDB_CURSOR_WITHOUT_XACT_BLK

If your application will not run properly with the extra commits added by EDB_COMMIT_AFTER_CURSOR, you may try setting EDB_ATTR_HOLD_CURSOR_ACTION to EDB_CURSOR_WITHOUT_XACT_BLK. With this action, the OCL will not begin a new transaction chain. If you create a WITH HOLD cursor immediately after committing or rolling back a transaction, the cursor will be created in its own transaction, the database server will commit that transaction, and the cursor will persist.

It is important to understand that you may still experience errors if the cursor declaration is not the first statement within a transaction – if you execute some other statement before declaring the cursor, the WITH HOLD cursor will be created in a transaction block and may be rolled back if an error occurs (or if your application calls OCITransRollback()).

Please note that you can set the EDB_HOLD_CURSOR_ACTION on the server level (OCIServer) or for each statement handle (OCIStmt). If the statement attribute is set to a value other than OCI_DEFAULT, the value is derived from the statement handle, otherwise (if the statement attribute is set to OCI_DEFAULT), the value is taken from the server handle. So you can define a server-wide default action by setting the attribute in the server handle, and leaving the attribute set to OCI_DEFAULT in the statement handles. You can use different values for each statement handle (or server handle) as you see fit.

EDB_ATTR_STMT_LVL_TX

Unless otherwise instructed, the OCL connector will ROLLBACK the current transaction whenever the server reports an error. If you choose, you can override the automatic ROLLBACK with the edb_stmt_level_tx parameter, which preserves modifications within a transaction, even if one (or several) statements raise an error within the transaction.

You can use the OCIServer attribute with OCIAttrSet() and OCIAttrGet() to enable or disable EDB_ATTR_STMT_LEVEL_TX. By default, edb_stmt_level_tx is disabled. To enable edb_stmt_level_tx, the client application must call OCIAttrSet():

OCIServer *server  = myServer;
ub1        enabled = 1;

OCIAttrSet(server, OCI_HTYPE_SERVER, &enabled,
  sizeof(enabled), EDB_ATTR_STMT_LEVEL_TX, err);

To disable edb_stmt_level_tx:

OCIServer *server  = myServer;
ub1        enabled = 0;

OCIAttrSet(server, OCI_HTYPE_SERVER, &enabled,
  sizeof(enabled), EDB_ATTR_STMT_LEVEL_TX, err);

Bind, Define and Describe Functions

Function	Description
OCIBindByName	Bind by name.
OCIBindByPos	Bind by position.
OCIBindDynamic	Set additional attributes after bind.
OCIBindArrayOfStruct	Bind an array of structures for bulk operations.
OCIDefineArrayOfStruct	Specify the attributes of an array.
OCIDefineByPos	Define an output variable association.
OCIDefineDynamic	Set additional attributes for define.
OCIDescribeAny	Describe existing schema objects.
OCIStmtGetBindInfo	Get bind and indicator variable names and handle.
OCIUserCallbackRegister	Define a user-defined callback.

Statement Functions

Function	Description
OCIStmtExecute	Execute a prepared SQL statement.
OCIStmtFetch	Fetch rows of data (deprecated).
OCIStmtFetch2	Fetch rows of data.
OCIStmtPrepare	Prepare a SQL statement.
OCIStmtPrepare2	Prepare a SQL statement.
OCIStmtRelease	Release a statement handle.

Transaction Functions

Function	Description
OCITransCommit	Commit a transaction.
OCITransRollback	Roll back a transaction.

XA Functions

Function	Description
xaoEnv	Returns OCL environment handle.
xaoSvcCtx	Returns OCL service context.

xaoSvcCtx

In order to use the xaoSvcCtx function, extensions in the xaoSvcCtx or xa_open connection string format must be provided as follows:

Oracle_XA{+<required_fields> ...}

Where required_fields are the following:

HostName=host_ip_address specifies the IP address of the Advanced Server database.

PortNumber=host_port_number specifies the port number on which Advanced Server is running.

SqlNet=dbname specifies the database name.

Acc=P/username/password specifies the database username and password. password may be omitted in which case the field is specified as Acc=P/username/.

AppName=app_id specifies a number that identifies the application.

The following is an example of the connection string:

Oracle_XA+HostName=192.168.1.1+PortNumber=1533+SqlNet=XE+Acc=P/user/password+AppName=1234

Date and Datetime Functions

Function	Description
OCIDateAddDays	Add or subtract a number of days.
OCIDateAddMonths	Add or subtract a number of months.
OCIDateAssign	Assign a date.
OCIDateCheck	Check if the given date is valid.
OCIDateCompare	Compare two dates.
OCIDateDaysBetween	Find the number of days between two dates.
OCIDateFromText	Convert a string to a date.
OCIDateGetDate	Get the date portion of a date.
OCIDateGetTime	Get the time portion of a date.
OCIDateLastDay	Get the date of the last day of the month.
OCIDateNextDay	Get the date of the next day.
OCIDateSetDate	Set the date portion of a date.
OCIDateSetTime	Set the time portion of a date.
OCIDateSysDate	Get the current system date and time.
OCIDateToText	Convert a date to a string.
OCIDateTimeAssign	Perform datetime assignment.
OCIDateTimeCheck	Check if the date is valid.
OCIDateTimeCompare	Compare two datetime values.
OCIDateTimeConstruct	Construct a datetime descriptor.
OCIDateTimeConvert	Convert one datetime type to another.
OCIDateTimeFromArray	Convert an array of size OCI_DT_ARRAYLEN to an OCIDateTime descriptor.
OCIDateTimeFromText	Convert the given string to Oracle datetime type in the OCIDateTime descriptor according to the specified format.
OCIDateTimeGetDate	Get the date portion of a datetime value.
OCIDateTimeGetTime	Get the time portion of a datetime value.
OCIDateTimeGetTimeZoneName	Get the time zone name portion of a datetime value.
OCIDateTimeGetTimeZoneOffset	Get the time zone (hour, minute) portion of a datetime value.
OCIDateTimeSubtract	Take two datetime values as input and return their difference as an interval.
OCIDateTimeSysTimeStamp	Get the system current date and time as a timestamp with time zone.
OCIDateTimeToArray	Convert an OCIDateTime descriptor to an array.
OCIDateTimeToText	Convert the given date to a string according to the specified format.

Interval Functions

Function	Description
OCIIntervalAdd	Adds two interval values.
OCIIntervalAssign	Copies one interval value into another interval value.
OCIIntervalCompare	Compares two interval values.
OCIIntervalGetDaySecond	Extracts days, hours, minutes, seconds and fractional seconds from an interval.
OCIIntervalSetDaySecond	Modifies days, hours, minutes, seconds and fractional seconds in an interval.
OCIIntervalGetYearMonth	Extracts year and month values from an interval.
OCIIntervalSetYearMonth	Modifies year and month values in an interval.
OCIIntervalDivide	Implements division of OCIInterval values by OCINumber values.
OCIIntervalMultiply	Implements multiplication of OCIInterval values by OCINumber values.
OCIIntervalSubtract	Subtracts one interval value from another interval value.
OCIIntervalToText	Extrapolates a character string from an interval.
OCIIntervalCheck	Verifies the validity of an interval value.
OCIIntervalToNumber	Converts an OCIInterval value into a OCINumber value.
OCIIntervalFromNumber	Converts a OCINumber value into an OCIInterval value.
OCIDateTimeIntervalAdd	Adds an OCIInterval value to an OCIDatetime value, resulting in an OCIDatetime value.
OCIDateTimeIntervalSub	Subtracts an OCIInterval value from an OCIDatetime value, resulting in an OCIDatetime value.
OCIIntervalFromText	Converts a text string into an interval.
OCIIntervalFromTZ	Converts a time zone specification into an interval value.

Number Functions

Function	Description
OCINumberAbs	Compute the absolute value.
OCINumberAdd	Adds NUMBERs.
OCINumberArcCos	Compute the arc cosine.
OCINumberArcSin	Compute the arc sine.
OCINumberArcTan	Compute the arc tangent.
OCINumberArcTan2	Compute the arc tangent of two NUMBERs.
OCINumberAssign	Assign one NUMBER to another.
OCINumberCeil	Compute the ceiling of NUMBER.
OCINumberCmp	Compare NUMBERs.
OCINumberCos	Compute the cosine.
OCINumberDec	Decrement a NUMBER.
OCINumberDiv	Divide two NUMBERs.
OCINumberExp	Raise e to the specified NUMBER power.
OCINumberFloor	Compute the floor of a NUMBER.
OCINumberFromInt	Convert an integer to an Oracle NUMBER.
OCINumberFromReal	Convert a real to an Oracle NUMBER.
OCINumberFromText	Convert a string to an Oracle NUMBER.
OCINumberHypCos	Compute the hyperbolic cosine.
OCINumberHypSin	Compute the hyperbolic sine.
OCINumberHypTan	Compute the hyperbolic tangent.
OCINumberInc	Increments a NUMBER.
OCINumberIntPower	Raise a given base to an integer power.
OCINumberIsInt	Test if a NUMBER is an integer.
OCINumberIsZero	Test if a NUMBER is zero.
OCINumberLn	Compute the natural logarithm.
OCINumberLog	Compute the logarithm to an arbitrary base.
OCINumberMod	Modulo division.
OCINumberMul	Multiply NUMBERs.
OCINumberNeg	Negate a NUMBER.
OCINumberPower	Exponentiation to base e.
OCINumberPrec	Round a NUMBER to a specified number of decimal places.
OCINumberRound	Round a NUMBER to a specified decimal place.
OCINumberSetPi	Initialize a NUMBER to Pi.
OCINumberSetZero	Initialize a NUMBER to zero.
OCINumberShift	Multiply by 10, shifting specified number of decimal places.
OCINumberSign	Obtain the sign of a NUMBER.
OCINumberSin	Compute the sine.
OCINumberSqrt	Compute the square root of a NUMBER.
OCINumberSub	Subtract NUMBERs.
OCINumberTan	Compute the tangent.
OCINumberToInt	Convert a NUMBER to an integer.
OCINumberToReal	Convert a NUMBER to a real.
OCINumberToRealArray	Convert an array of NUMBER to a real array.
OCINumberToText	Converts a NUMBER to a string.
OCINumberTrunc	Truncate a NUMBER at a specified decimal place.

String Functions

Function	Description
OCIStringAllocSize	Get allocated size of string memory in bytes.
OCIStringAssign	Assign string to a string.
OCIStringAssignText	Assign text string to a string.
OCIStringPtr	Get string pointer.
OCIStringResize	Resize string memory.
OCIStringSize	Get string size.

Cartridge Services and File I/O Interface Functions

Function	Description
OCIFileClose	Close an open file.
OCIFileExists	Test to see if the file exists.
OCIFileFlush	Write buffered data to a file.
OCIFileGetLength	Get the length of a file.
OCIFileInit	Initialize the OCIFile package.
OCIFileOpen	Open a file.
OCIFileRead	Read from a file into a buffer.
OCIFileSeek	Change the current position in a file.
OCIFileTerm	Terminate the OCIFile package.
OCIFileWrite	Write buflen bytes into the file.

LOB Functions

Function	Description
OCILobRead	Returns a LOB value (or a portion of a LOB value).
OCILOBWriteAppend	Adds data to a LOB value.
OCILobGetLength	Returns the length of a LOB value.
OCILobTrim	Trims data from the end of a LOB value.
OCILobOpen	Opens a LOB value for use by other LOB functions.
OCILobClose	Closes a LOB value.

Miscellaneous Functions

Function	Description
OCIClientVersion	Return client library version.
OCIErrorGet	Return error message.
OCIPGErrorGet	Return native error messages reported by libpq or the server. The signature is: sword OCIPGErrorGet(dvoid *hndlp, ub4 recordno, OraText *errcodep,ub4 errbufsiz, OraText *bufp, ub4 bufsiz, ub4 type)
OCIPasswordChange	Change password.
OCIPing	Confirm that the connection and server are active.
OCIServerVersion	Get the Oracle version string.

Supported Data Types

Function	Description
ANSI_DATE	ANSI date
SQLT_AFC	ANSI fixed character
SQLT_AVC	ANSI variable character
SQLT_BDOUBLE	Binary double
SQLT_BIN	Binary data
SQLT_BFLOAT	Binary float
SQLT_CHR	Character string
SQLT_DAT	Oracle date
SQLT_DATE	ANSI date
SQLT_FLT	Float
SQLT_INT	Integer
SQLT_LBI	Long binary
SQLT_LNG	Long
SQLT_LVB	Longer long binary
SQLT_LVC	Longer longs (character)
SQLT_NUM	Oracle numeric
SQLT_ODT	OCL date type
SQLT_STR	Zero-terminated string
SQLT_TIMESTAMP	Timestamp
SQLT_TIMESTAMP_TZ	Timestamp with time zone
SQLT_TIMESTAMP_LTZ	Timestamp with local time zone
SQLT_UIN	Unsigned integer
SQLT_VBI	VCS format binary
SQLT_VCS	Variable character
SQLT_VNU	Number with preceding length byte
SQLT_VST	OCL string type