Postgresql 中文操作指南
SET DESCRIPTOR
SET DESCRIPTOR — 在 SQL 描述符区域中设置信息
SET DESCRIPTOR — set information in an SQL descriptor area
Synopsis
SET DESCRIPTOR descriptor_name descriptor_header_item = value [, ... ]
SET DESCRIPTOR descriptor_name VALUE number descriptor_item = value [, ...]Description
SET DESCRIPTOR 使用值填充 SQL 描述符区域。描述符区域然后通常用于绑定准备的查询执行中的参数。
SET DESCRIPTOR populates an SQL descriptor area with values. The descriptor area is then typically used to bind parameters in a prepared query execution.
此命令有两种形式：第一种形式适用于独立于特定数据的描述符“标头”。第二种形式为使用数字标识的特定数据分配值。
This command has two forms: The first form applies to the descriptor “header”, which is independent of a particular datum. The second form assigns values to particular datums, identified by number.
Parameters
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descriptor_name #
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A descriptor name.
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descriptor_header_item #
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A token identifying which header information item to set. Only COUNT, to set the number of descriptor items, is currently supported.
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number #
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The number of the descriptor item to set. The count starts at 1.
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descriptor_item #
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A token identifying which item of information to set in the descriptor. See Section 36.7.1 for a list of supported items.
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value #
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A value to store into the descriptor item. This can be an SQL constant or a host variable.
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Examples
EXEC SQL SET DESCRIPTOR indesc COUNT = 1;
EXEC SQL SET DESCRIPTOR indesc VALUE 1 DATA = 2;
EXEC SQL SET DESCRIPTOR indesc VALUE 1 DATA = :val1;
EXEC SQL SET DESCRIPTOR indesc VALUE 2 INDICATOR = :val1, DATA = 'some string';
EXEC SQL SET DESCRIPTOR indesc VALUE 2 INDICATOR = :val2null, DATA = :val2;