dbStatement

data type

Library: Database access (OMDB legacy)
Include: omdb.xin

Purpose

The dbStatement OMX component is used to receive the compiled SQL statement from dbStatementCompile. Through this OMX component, the same SQL statement may be executed multiple times without the need to compile the statement at every execution. For some programs, this reduction in processing overhead can be significant.

Usage Notes

To use this component in your program, you must include in your program:

      include "omdb.xin"

To create a dbStatement, use the dbStatementCompile function. The resulting OMX component is a link to the compiled SQL statement. The statement can then be executed either by calling the dbStatementExecute function or by calling the dbStatementStreamingExecute function. All placeholder values must be specified at this time. If the statement is a query, the query results are retrieved through a dbField shelf. When you have finished using the statement, you can use dbStatementDiscard to release the resources used by the dbStatement OMX component. This is not generally required, as the OMX also does an automatic discard.

The OmniMark Database dynamic link library file ("omdb.dll" or "omdb.so") creates the dbStatement OMX component. The related include file ("omdb.xin") defines the interface to that component.

Please refer to OMX Components for a general description of OMX components and how they are used.

Related OMDB library functions:

The functions

dbStatementCompile - compile an SQL statement.
dbStatementDiscard - discard a compiled SQL statement.

are used to establish and discard dbStatement components. The dbStatement objects are used by the following OMDB library functions:

dbStatementExecute - execute a compiled SQL statement, passing in parameters up front.
dbStatementStreamingExecute - execute a compiled SQL statement, streaming in parameters dynamically.