Postgres-XC 1.0.2 Documentation
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dblink_build_sql_delete

Name

dblink_build_sql_delete -- builds a DELETE statement using supplied values for primary key field values

Synopsis

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

Description

Note: The following description applies only to Postgres-XC

dblink module has not been tested with Postges-XC yet. Although there're no reason that dblink does not run in Postgres-XC, the development team leaves the test and the use of this module entirely to users.

This section is identical to the corresponding PostgreSQL reference manual.

Note: The following description applies only to PostgreSQL

dblink_build_sql_delete can be useful in doing selective replication of a local table to a remote database. It builds a SQL DELETE command that will delete the row with the given primary key values.

Arguments

Note: The following description applies only to PostgreSQL

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.

tgt_pk_att_vals_array

Values of the primary key fields to be used in the resulting DELETE command. Each field is represented in text form.

Return Value

Note: The following description applies only to PostgreSQL

Returns the requested SQL statement as text.

Notes

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.

Example

Note: The following description applies only to PostgreSQL

SELECT dblink_build_sql_delete('"MyFoo"', '1 2', 2, '{"1", "b"}');
           dblink_build_sql_delete
---------------------------------------------
 DELETE FROM "MyFoo" WHERE f1='1' AND f2='b'
(1 row)
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