| Specification: | DB2 CLI 2.1 |
|
SQLGetSubString() is used to retrieve a portion of a large object value, referenced by a large object locator that has been returned from the server (returned by a fetch or a previous SQLGetSubString() call) during the current transaction.
Syntax
SQLRETURN SQLGetSubString (
SQLHSTMT StatementHandle, /* hstmt */
SQLSMALLINT LocatorCType,
SQLINTEGER SourceLocator,
SQLUINTEGER FromPosition,
SQLUINTEGER ForLength,
SQLSMALLINT TargetCType,
SQLPOINTER DataPtr, /* rgbValue */
SQLINTEGER BufferLength, /* cbValueMax */
SQLINTEGER FAR *StringLength,
SQLINTEGER FAR *IndicatorValue);
Function Arguments
Table 120. SQLGetSubString Arguments
| Data Type | Argument | Use | Description | ||
|---|---|---|---|---|---|
| SQLHSTMT | StatementHandle | input | Statement handle. This can be any statement handle which has been allocated but which does not currently have a prepared statement assigned to it. | ||
| SQLSMALLINT | LocatorCType | input | The C type of the source LOB locator. This may be:
| ||
| SQLINTEGER | Locator | input | Locator must be set to the source LOB locator value. | ||
| SQLUINTEGER | FromPosition | input | For BLOBs and CLOBs, this is the position of the first byte to be returned by the function. For DBCLOBs, this is the first character. The start byte or character is numbered 1. | ||
| SQLUINTEGER | ForLength | input | This is the length of the string to be returned by the function.
For BLOBs and CLOBs, this is the length in bytes. For DBCLOBs, this is
the length in characters.
If FromPosition is less than the length of the source string but FromPosition + ForLength - 1 extends beyond the end of the source string, the result is padded on the right with the necessary number of characters (X'00' for BLOBs, single byte blank character for CLOBs, and double byte blank character for DBCLOBs). | ||
| SQLSMALLINT | TargetCType | input | The C data type of the DataPtr. The target must always be either a LOB locator C buffer type (SQL_C_CLOB_LOCATOR, (SQL_C_BLOB_LOCATOR, (SQL_C_DBCLOB_LOCATOR) or a C string variable (SQL_C_CHAR for CLOB, SQL_C_BINARY for BLOB, and SQL_C_DBCHAR for DBCLOB). | ||
| SQLPOINTER | DataPtr | output | Pointer to the buffer where the retrieved string value or a LOB locator is to be stored. | ||
| SQLINTEGER | BufferLength | input | Maximum size of the buffer pointed to by DataPtr in bytes. | ||
| SQLINTEGER * | StringLength | output | The length of the returned information in DataPtr in
bytesa if the target C buffer type is intended for a binary or
character string variable and not a locator value.
If the pointer is set to NULL, nothing is returned. | ||
| SQLINTEGER * | IndicatorValue | output | Always set to zero. | ||
| |||||
Usage
SQLGetSubString() is used to obtain any portion of the string that is represented by the LOB locator. There are two choices for the target:
SQLGetSubString() can be used as an alternative to SQLGetData for getting data in pieces. In this case a column is first bound to a LOB locator, which is then used to fetch the LOB as a whole or in pieces.
The Locator argument can contain any valid LOB locator which has not been explicitly freed using a FREE LOCATOR statement nor implicitly freed because the transaction during which it was created has terminated.
The statement handle must not have been associated with any prepared statements or catalog function calls.
Return Codes
Diagnostics
Table 121. SQLGetSubString SQLSTATEs
| SQLSTATE | Description | Explanation |
|---|---|---|
| 01004 | Data truncated. | The amount of data to be returned is longer than BufferLength. Actual length available for return is stored in StringLength. |
| 07006 | Invalid conversion. | The value specified for TargetCType was not SQL_C_CHAR,
SQL_C_BINARY, SQL_C_DBCHAR or a LOB locator.
The value specified for TargetCType is inappropriate for the source (for example SQL_C_DBCHAR for a BLOB column). |
| 22011 | A substring error occurred. | FromPosition is greater than the of length of the source string. |
| 40003 08S01 | Communication link failure. | The communication link between the application and data source failed before the function completed. |
| 58004 | Unexpected system failure. | Unrecoverable system error. |
| HY001 | Memory allocation failure. | DB2 CLI is unable to allocate memory required to support execution or completion of the function. |
| HY003 | Program type out of range. | LocatorCType is not one of SQL_C_CLOB_LOCATOR, SQL_C_BLOB_LOCATOR, or SQL_C_DBCLOB_LOCATOR. |
| HY009 | Invalid argument value. | The value specified for FromPosition or for ForLength was not a positive integer. |
| HY010 | Function sequence error. | The specified StatementHandle is not in an allocated
state.
The function was called while in a data-at-execute (SQLParamData(), SQLPutData()) operation. The function was called while within a BEGIN COMPOUND and END COMPOUND SQL operation. An asynchronously executing function (not this one) was called for the StatementHandle and was still executing when this function was called. |
| HY013 | Unexpected memory handling error. | DB2 CLI was unable to access memory required to support execution or completion of the function. |
| HY090 | Invalid string or buffer length. | The value of BufferLength was less than 0. |
| HYC00 | Driver not capable. | The application is currently connected to a data source that does not support large objects. |
| 0F001 | No locator currently assigned | The value specified for Locator is not currently a LOB locator. |
Restrictions
This function is not available when connected to a DB2 server that does not support Large Objects. Call SQLGetFunctions() with the function type set to SQL_API_SQLGETSUBSTRING and check the fExists output argument to determine if the function is supported for the current connection.
Refer to Example.
References