I noted there was an inquiry as to how to copy or clone_schema
an entire schema. The standard method for doing that is to
1. pg_dump the schema in plain format
2. edit the dump file and change all occurrences of the schema name
3. reload the dump into the new schema.
The attached function is an alternate method for doing that.
It is a revision of the clone_schema by by Emanuel '3manuek'
from https://wiki.postgresql.org/wiki/Clone_schema
Originally, it did not copy views, functions or data from
the source schema despite the claim that it "copies everything".
I've added error checking and verified that it now copies the
current sequnce values, table data, views and functions.
As always, use with caution.
--
*Melvin Davidson*
I reserve the right to fantasize. Whether or not you
wish to share my fantasy is entirely up to you.
-- Function: clone_schema(text, text)
-- DROP FUNCTION clone_schema(text, text);
CREATE OR REPLACE FUNCTION clone_schema(
source_schema text,
dest_schema text)
RETURNS void AS
$BODY$
-- by Emanuel '3manuek'
-- Revised by Melvin Davidson
-- This function will clone all sequences, tables, data, views & functions
from any existing schema to a new one
-- SAMPLE CALL:
-- SELECT clone_schema('public', 'new_schema');
DECLARE
src_oid oid;
func_oid oid;
object text;
buffer text;
srctbl text;
default_ text;
column_ text;
qry text;
dest_qry text;
v_def text;
seqval bigint;
sq_last_value bigint;
sq_max_value bigint;
sq_start_value bigint;
sq_increment_by bigint;
sq_min_value bigint;
sq_cache_value bigint;
sq_log_cnt bigint;
sq_is_called boolean;
sq_is_cycled boolean;
sq_cycled char(10);
BEGIN
-- Check that source_schema exists
SELECT oid INTO src_oid
FROM pg_namespace
WHERE nspname = quote_ident(source_schema);
IF NOT FOUND
THEN
RAISE NOTICE 'source schema % does not exist!', source_schema;
RETURN ;
END IF;
-- Check that dest_schema does not yet exist
PERFORM nspname
FROM pg_namespace
WHERE nspname = quote_ident(dest_schema);
IF FOUND
THEN
RAISE NOTICE 'dest schema % already exists!', dest_schema;
RETURN ;
END IF;
EXECUTE 'CREATE SCHEMA ' || quote_ident(dest_schema) ;
-- Create sequences
-- TODO: Find a way to make this sequence's owner is the correct table.
FOR object IN
SELECT sequence_name::text
FROM information_schema.sequences
WHERE sequence_schema = quote_ident(source_schema)
LOOP
EXECUTE 'CREATE SEQUENCE ' || quote_ident(dest_schema) || '.' ||
quote_ident(object);
srctbl := quote_ident(source_schema) || '.' || quote_ident(object);
EXECUTE 'SELECT last_value, max_value, start_value, increment_by,
min_value, cache_value, log_cnt, is_cycled, is_called
FROM ' || quote_ident(source_schema) || '.' ||
quote_ident(object) || ';'
INTO sq_last_value, sq_max_value, sq_start_value,
sq_increment_by, sq_min_value, sq_cache_value, sq_log_cnt, sq_is_cycled,
sq_is_called ;
IF sq_is_cycled
THEN
sq_cycled := 'CYCLE';
ELSE
sq_cycled := 'NO CYCLE';
END IF;
EXECUTE 'ALTER SEQUENCE ' || quote_ident(dest_schema) || '.' ||
quote_ident(object)
|| ' INCREMENT BY ' || sq_increment_by
|| ' MINVALUE ' || sq_min_value
|| ' MAXVALUE ' || sq_max_value
|| ' START WITH ' || sq_start_value
|| ' RESTART ' || sq_min_value
|| ' CACHE ' || sq_cache_value
|| sq_cycled || ' ;' ;
buffer := quote_ident(dest_schema) || '.' || quote_ident(object);
EXECUTE 'SELECT setval( ''' || buffer || ''', ' || sq_last_value || ', ' ||
sq_is_called || ');' ;
END LOOP;
-- Create tables
FOR object IN
SELECT TABLE_NAME::text
FROM information_schema.tables
WHERE table_schema = quote_ident(source_schema)
AND table_type = 'BASE TABLE'
LOOP
buffer := dest_schema || '.' || quote_ident(object);
EXECUTE 'CREATE TABLE ' || buffer || ' (LIKE ' ||
quote_ident(source_schema) || '.' || quote_ident(object) || ' INCLUDING
CONSTRAINTS INCLUDING INDEXES INCLUDING DEFAULTS)';
-- Insert records from source table
EXECUTE 'INSERT INTO ' || buffer || ' SELECT * FROM ' ||
quote_ident(source_schema) || '.' || quote_ident(object) || ';';
FOR column_, default_ IN
SELECT column_name::text,
REPLACE(column_default::text, source_schema, dest_schema)
FROM information_schema.COLUMNS
WHERE table_schema = dest_schema
AND TABLE_NAME = object
AND column_default LIKE 'nextval(%' || quote_ident(source_schema) ||
'%::regclass)'
LOOP
EXECUTE 'ALTER TABLE ' || buffer || ' ALTER COLUMN ' || column_ || ' SET
DEFAULT ' || default_;
END LOOP;
END LOOP;
-- Create views
FOR object IN
SELECT table_name::text,
view_definition
FROM information_schema.views
WHERE table_schema = quote_ident(source_schema)
LOOP
buffer := dest_schema || '.' || quote_ident(object);
SELECT view_definition INTO v_def
FROM information_schema.views
WHERE table_schema = quote_ident(source_schema)
AND table_name = quote_ident(object);
EXECUTE 'CREATE OR REPLACE VIEW ' || buffer || ' AS ' || v_def || ';' ;
END LOOP;
-- Create functions
FOR func_oid IN
SELECT oid
FROM pg_proc
WHERE pronamespace = src_oid
LOOP
SELECT pg_get_functiondef(func_oid) INTO qry;
SELECT replace(qry, source_schema, dest_schema) INTO dest_qry;
EXECUTE dest_qry;
END LOOP;
RETURN;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION clone_schema(text, text)
OWNER TO postgres;
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