Copy schema and create new schema with different name in the same data base

I there a way to copy the existing schema and generate new schema with another name in the same database in postgres.

5 Answers
5

Use pg_dump to dump your current schema in a SQL-formated file. Open the file, replace the schemaname with the new name and excute this script in your database to create the new schema and all other objects inside this schema.

oldschema

newschema

TEMPLATE

CREATE DATABASE dbname_target TEMPLATE dbname_source;

This will copy data too. So you might want to create your own template if you need many copies. See Template Databases.

${schema_name}

schema

I ran a few tests and found the result is referencing the source schema. So here's my improved version:

-- Function: clone_schema(source text, dest text, include_records boolean default true, show_details boolean default false)

-- DROP FUNCTION clone_schema(text, text, boolean, boolean);

CREATE OR REPLACE FUNCTION clone_schema(
source_schema text,
dest_schema text,
include_recs boolean DEFAULT true,
show_details boolean DEFAULT false)
RETURNS void AS
$BODY$

-- 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');
-- SELECT clone_schema('public', 'new_schema', TRUE);
-- SELECT clone_schema('public', 'new_schema', TRUE, TRUE);

DECLARE
src_oid oid;
tbl_oid oid;
func_oid oid;
object text;
buffer text;
srctbl text;
default_ text;
column_ text;
qry text;
xrec record;
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);
rec record;
source_schema_dot text = source_schema || '.';
dest_schema_dot text = dest_schema || '.';

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) ;

-- Defaults search_path to destination schema
PERFORM set_config('search_path', dest_schema, true);

-- 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);
IF include_recs
THEN
EXECUTE 'SELECT setval( ''' || buffer || ''', ' || sq_last_value || ', ' || sq_is_called || ');' ;
ELSE
EXECUTE 'SELECT setval( ''' || buffer || ''', ' || sq_start_value || ', ' || sq_is_called || ');' ;
END IF;
IF show_details THEN RAISE NOTICE 'Sequence created: %', object; END IF;
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 ALL)';

IF include_recs
THEN
-- Insert records from source table
EXECUTE 'INSERT INTO ' || buffer || ' SELECT * FROM ' || quote_ident(source_schema) || '.' || quote_ident(object) || ';';
END IF;

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;

IF show_details THEN RAISE NOTICE 'base table created: %', object; END IF;

END LOOP;

-- add FK constraint
FOR xrec IN
SELECT ct.conname as fk_name, rn.relname as tb_name, 'ALTER TABLE ' || quote_ident(dest_schema) || '.' || quote_ident(rn.relname)
|| ' ADD CONSTRAINT ' || quote_ident(ct.conname) || ' ' || replace(pg_get_constraintdef(ct.oid), source_schema_dot, '') || ';' as qry
FROM pg_constraint ct
JOIN pg_class rn ON rn.oid = ct.conrelid
WHERE connamespace = src_oid
AND rn.relkind = 'r'
AND ct.contype = 'f'

LOOP
IF show_details THEN RAISE NOTICE 'Creating FK constraint %.%...', xrec.tb_name, xrec.fk_name; END IF;
--RAISE NOTICE 'DEF: %', xrec.qry;
EXECUTE xrec.qry;
END LOOP;

-- Create functions
FOR xrec IN
SELECT proname as func_name, oid as func_oid
FROM pg_proc
WHERE pronamespace = src_oid

LOOP
IF show_details THEN RAISE NOTICE 'Creating function %...', xrec.func_name; END IF;
SELECT pg_get_functiondef(xrec.func_oid) INTO qry;
SELECT replace(qry, source_schema_dot, '') INTO dest_qry;
EXECUTE dest_qry;
END LOOP;

-- add Table Triggers
FOR rec IN
SELECT
trg.tgname AS trigger_name,
tbl.relname AS trigger_table,

CASE
WHEN trg.tgenabled='O' THEN 'ENABLED'
ELSE 'DISABLED'
END AS status,
CASE trg.tgtype::integer & 1
WHEN 1 THEN 'ROW'::text
ELSE 'STATEMENT'::text
END AS trigger_level,
CASE trg.tgtype::integer & 66
WHEN 2 THEN 'BEFORE'
WHEN 64 THEN 'INSTEAD OF'
ELSE 'AFTER'
END AS action_timing,
CASE trg.tgtype::integer & cast(60 AS int2)
WHEN 16 THEN 'UPDATE'
WHEN 8 THEN 'DELETE'
WHEN 4 THEN 'INSERT'
WHEN 20 THEN 'INSERT OR UPDATE'
WHEN 28 THEN 'INSERT OR UPDATE OR DELETE'
WHEN 24 THEN 'UPDATE OR DELETE'
WHEN 12 THEN 'INSERT OR DELETE'
WHEN 32 THEN 'TRUNCATE'
END AS trigger_event,
'EXECUTE PROCEDURE ' || (SELECT nspname FROM pg_namespace where oid = pc.pronamespace )
|| '.' || proname || '('
|| regexp_replace(replace(trim(trailing '00' from encode(tgargs,'escape')), '00',','),'{(.+)}','''{1}''','g')
|| ')' as action_statement

FROM pg_trigger trg
JOIN pg_class tbl on trg.tgrelid = tbl.oid
JOIN pg_proc pc ON pc.oid = trg.tgfoid
WHERE trg.tgname not like 'RI_ConstraintTrigger%'
AND trg.tgname not like 'pg_sync_pg%'
AND tbl.relnamespace = (SELECT oid FROM pg_namespace where nspname = quote_ident(source_schema) )

LOOP
buffer := dest_schema || '.' || quote_ident(rec.trigger_table);
IF show_details THEN RAISE NOTICE 'Creating trigger % % % ON %...', rec.trigger_name, rec.action_timing, rec.trigger_event, rec.trigger_table; END IF;
EXECUTE 'CREATE TRIGGER ' || rec.trigger_name || ' ' || rec.action_timing
|| ' ' || rec.trigger_event || ' ON ' || buffer || ' FOR EACH '
|| rec.trigger_level || ' ' || replace(rec.action_statement, source_schema_dot, '');

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 replace(view_definition, source_schema_dot, '') INTO v_def
FROM information_schema.views
WHERE table_schema = quote_ident(source_schema)
AND table_name = quote_ident(object);
IF show_details THEN RAISE NOTICE 'Creating view % AS %', object, regexp_replace(v_def, '[nr]+', ' ', 'g'); END IF;
EXECUTE 'CREATE OR REPLACE VIEW ' || buffer || ' AS ' || v_def || ';' ;

END LOOP;

RETURN;

END;

$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;


Check out this PostgreSQL's wiki page. It contains a function for clone_schema as you required, but this function only clones tables. The page refers to this post, which contains a function that clones everything you need for the schema. This function worked well for me, I managed to execute it with JDBC API.

clone_schema

But I had some problems when the schema names contained - or capital letters. After a research I found out that the source of the problem is quote_ident() method. I changes the clone_schema function to work with any schema names. I share the new function here, hope it will help somebody:

-

quote_ident()

clone_schema

-- Function: clone_schema(text, text)

-- DROP FUNCTION clone_schema(text, text);

CREATE OR REPLACE FUNCTION clone_schema(
source_schema text,
dest_schema text,
include_recs boolean)
RETURNS void AS
$BODY$

-- 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', TRUE);

DECLARE
src_oid oid;
tbl_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 = source_schema;
IF NOT FOUND
THEN
RAISE EXCEPTION '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 = dest_schema;
IF FOUND
THEN
RAISE EXCEPTION 'dest schema % already exists!', dest_schema;
RETURN ;
END IF;

EXECUTE 'CREATE SCHEMA "' || 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 = source_schema
LOOP
EXECUTE 'CREATE SEQUENCE "' || dest_schema || '".' || quote_ident(object);
srctbl := '"' || 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 "' || 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 "' || 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 := '"' || dest_schema || '".' || quote_ident(object);
IF include_recs
THEN
EXECUTE 'SELECT setval( ''' || buffer || ''', ' || sq_last_value || ', ' || sq_is_called || ');' ;
ELSE
EXECUTE 'SELECT setval( ''' || buffer || ''', ' || sq_start_value || ', ' || sq_is_called || ');' ;
END IF;

END LOOP;

-- Create tables
FOR object IN
SELECT TABLE_NAME::text
FROM information_schema.tables
WHERE table_schema = source_schema
AND table_type = 'BASE TABLE'

LOOP
buffer := '"' || dest_schema || '".' || quote_ident(object);
EXECUTE 'CREATE TABLE ' || buffer || ' (LIKE "' || source_schema || '".' || quote_ident(object)
|| ' INCLUDING ALL)';

IF include_recs
THEN
-- Insert records from source table
EXECUTE 'INSERT INTO ' || buffer || ' SELECT * FROM "' || source_schema || '".' || quote_ident(object) || ';';
END IF;

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(%"' || source_schema || '"%::regclass)'
LOOP
EXECUTE 'ALTER TABLE ' || buffer || ' ALTER COLUMN ' || column_ || ' SET DEFAULT ' || default_;
END LOOP;

END LOOP;

-- add FK constraint
FOR qry IN
SELECT 'ALTER TABLE "' || dest_schema || '".' || quote_ident(rn.relname)
|| ' ADD CONSTRAINT ' || quote_ident(ct.conname) || ' ' || pg_get_constraintdef(ct.oid) || ';'
FROM pg_constraint ct
JOIN pg_class rn ON rn.oid = ct.conrelid
WHERE connamespace = src_oid
AND rn.relkind = 'r'
AND ct.contype = 'f'

LOOP
EXECUTE qry;

END LOOP;


-- Create views
FOR object IN
SELECT table_name::text,
view_definition
FROM information_schema.views
WHERE table_schema = source_schema

LOOP
buffer := '"' || dest_schema || '".' || quote_ident(object);
SELECT view_definition INTO v_def
FROM information_schema.views
WHERE table_schema = 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, boolean)
OWNER TO postgres;


This seems to be the best solution I came up to.

The idea is to use pg_dump with -O (no owner) and -o (oids) options to get plain text output without source schema and owner information.

Such output i filter through sed replacing the default entry

SET search_path = source_schema, pg_catalog;


with command to create the new schema and set the default search path to it

CREATE SCHEMA new_schema;
SET search_path = new_schema, pg_catalog;


After that I redirect the stream to psql logging to desired user and database to which copy of the schema will be transfered.

The final command to copy schema 'public' to schema '2016' in the same database 'b1' looks like this:

pg_dump -U postgres -Oo -n public -d b1 | sed 's/SET search_path = public, pg_catalog;/CREATE SCHEMA "2016";SET search_path = "2016", pg_catalog;/' | psql -U postgres -d b1


Please note that GRANTS are not transfered from the source schema to the new one.

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.