Postgresql 中文操作指南

SPI_prepare_cursor

SPI_prepare_cursor — 准备一个语句，但不执行它

SPI_prepare_cursor — prepare a statement, without executing it yet

Synopsis

SPIPlanPtr SPI_prepare_cursor(const char * command, int nargs,
                              Oid * argtypes, int cursorOptions)

Description

SPI_prepare_cursor 与 SPI_prepare 相同，区别在于它还允许指定计划程序的“游标选项”参数。这是一种位掩码，它具有 nodes/parsenodes.h 中所示的值，用于 DeclareCursorStmt 的 options 字段。 SPI_prepare 始终将游标选项视为零。

SPI_prepare_cursor is identical to SPI_prepare, except that it also allows specification of the planner’s “cursor options” parameter. This is a bit mask having the values shown in nodes/parsenodes.h for the options field of DeclareCursorStmt. SPI_prepare always takes the cursor options as zero.

此函数现已弃用，建议使用 SPI_prepare_extended 。

This function is now deprecated in favor of SPI_prepare_extended.

Arguments

  • const char * _command_

    • command string

  • int _nargs_

    • number of input parameters ($1, $2, etc.)

  • Oid * _argtypes_

    • pointer to an array containing the OIDs of the data types of the parameters

  • int _cursorOptions_

    • integer bit mask of cursor options; zero produces default behavior

Return Value

SPI_prepare_cursor 具有与 SPI_prepare 相同的返回约定。

SPI_prepare_cursor has the same return conventions as SPI_prepare.

Notes

方便设置在 cursorOptions 中的位包括 CURSOR_OPT_SCROLL 、 CURSOR_OPT_NO_SCROLL 、 CURSOR_OPT_FAST_PLAN 、 CURSOR_OPT_GENERIC_PLAN 和 CURSOR_OPT_CUSTOM_PLAN 。特别是，请注意 CURSOR_OPT_HOLD 已被忽略。

Useful bits to set in cursorOptions include CURSOR_OPT_SCROLL, CURSOR_OPT_NO_SCROLL, CURSOR_OPT_FAST_PLAN, CURSOR_OPT_GENERIC_PLAN, and CURSOR_OPT_CUSTOM_PLAN. Note in particular that CURSOR_OPT_HOLD is ignored.