dblink_build_sql_insert — builds an INSERT statement using a local tuple, replacing the primary key field values with alternative supplied values
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
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 a 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.)
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.
Returns the requested SQL statement as text.
As of LightDB 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.
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)