Postgresql 中文操作指南

dblink_build_sql_insert

dblink_build_sql_insert —使用本地元组构建 INSERT 语句，将主键字段值替换为替代提供的 值。

dblink_build_sql_insert — builds an INSERT statement using a local tuple, replacing the primary key field values with alternative supplied values

Synopsis

dblink_build_sql_insert(text relname,
                        int2vector primary_key_attnums,
                        integer num_primary_key_atts,
                        text[] src_pk_att_vals_array,
                        text[] tgt_pk_att_vals_array) returns text

Description

dblink_build_sql_insert 可用于执行本地表到远程数据库的选择性复制。它基于主键从本地表选择一行，然后构建 SQL INSERT 命令，该命令将复制该行，但将主键值替换为最后一个参数中的值。（如需制作行的精确副本，则只需对最后两个参数指定相同的值。）

dblink_build_sql_insert can be useful in doing selective replication of a local table to a remote database. It selects a row from the local table based on primary key, and then builds an SQL INSERT command that will duplicate that row, but with the primary key values replaced by the values in the last argument. (To make an exact copy of the row, just specify the same values for the last two arguments.)

Arguments

  • relname

    • Name of a local relation, for example foo or myschema.mytab. Include double quotes if the name is mixed-case or contains special characters, for example "FooBar"; without quotes, the string will be folded to lower case.

  • primary_key_attnums

    • Attribute numbers (1-based) of the primary key fields, for example 1 2.

  • num_primary_key_atts

    • The number of primary key fields.

  • src_pk_att_vals_array

    • Values of the primary key fields to be used to look up the local tuple. Each field is represented in text form. An error is thrown if there is no local row with these primary key values.

  • tgt_pk_att_vals_array

    • Values of the primary key fields to be placed in the resulting INSERT command. Each field is represented in text form.

Return Value

返回所请求的 SQL 语句作为文本。

Returns the requested SQL statement as text.

Notes

截至 PostgreSQL 9.0， primary_key_attnums 中的属性编号被解释为逻辑列编号，对应于该列在 SELECT * FROM relname 中的位置。以前版本将数字解释为物理列位置。如果在表的生命周期内删除了指示列左侧的任何列，则会有差异。

As of PostgreSQL 9.0, the attribute numbers in primary_key_attnums are interpreted as logical column numbers, corresponding to the column’s position in SELECT * FROM relname. Previous versions interpreted the numbers as physical column positions. There is a difference if any column(s) to the left of the indicated column have been dropped during the lifetime of the table.

Examples

SELECT dblink_build_sql_insert('foo', '1 2', 2, '{"1", "a"}', '{"1", "b''a"}');
             dblink_build_sql_insert
--------------------------------------------------
 INSERT INTO foo(f1,f2,f3) VALUES('1','b''a','1')
(1 row)