253 lines
10 KiB
PL/PgSQL
253 lines
10 KiB
PL/PgSQL
DROP FUNCTION IF EXISTS public.generate_partitioning_of_an_existing_table_by_date_unix_time(text, text, integer, integer, text, boolean);
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CREATE OR REPLACE FUNCTION public.generate_partitioning_of_an_existing_table_by_date_unix_time(
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tablename text,
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columnname text,
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start_year integer,
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end_year integer,
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step text,
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droptable boolean DEFAULT false)
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RETURNS void
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LANGUAGE 'plpgsql'
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VOLATILE PARALLEL UNSAFE
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AS $BODY$
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declare old_tablename TEXT;
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new_tablename TEXT;
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partition_tablename TEXT;
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start_interval TEXT;
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end_interval TEXT;
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interations INTEGER;
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i INTEGER;
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sql_str TEXT = '';
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receive_constraints TEXT;
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receive_triggers TEXT;
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toBeDeleted_constraints TEXT;
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lastvalue INTEGER;
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exists_sequence TEXT;
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tmp_sql VARCHAR;
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renamed_indexes TEXT;
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renamed_constraints TEXT;
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toBeCreated_indexes TEXT;
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start_unix_time TEXT;
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end_unix_time TEXT;
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primary_key TEXT;
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sequence_id TEXT;
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BEGIN
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IF start_year > end_year THEN
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RAISE NOTICE '%', 'start_year > end_year';
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RETURN;
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END IF;
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primary_key := '"posID"';
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sequence_id := '_posID_seq';
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new_tablename := 'new_' || tablename;
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sql_str := format('-- create a new table having the same structure with specified table ' || CHR(13) ||
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'CREATE TABLE ' || new_tablename || '(LIKE ' || tablename || ' INCLUDING DEFAULTS INCLUDING CONSTRAINTS) PARTITION BY RANGE(' || columnname || ');' || CHR(13) || CHR(13) ||
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'-- create partiton for all other records that dont match with the partition condition' || CHR(13) ||
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'CREATE TABLE ' || tablename || '_default PARTITION OF ' || new_tablename || ' DEFAULT; ') || CHR(13);
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sql_str := sql_str || CHR(13) || get_query_partitioning_of_an_existing_table_by_date_unix_time(tablename , new_tablename, start_year, end_year, step);
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sql_str := sql_str || CHR(13) ||
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'-- copy data into the new table ' || CHR(13) ||
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'INSERT INTO ' || new_tablename || '(SELECT * FROM ' || tablename || '); ' || CHR(13) ;
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RAISE NOTICE '%', sql_str;
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-- execute the query
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EXECUTE sql_str;
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--===========================================================
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-- build the commands to rename the indexes
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--===========================================================
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old_tablename := tablename;
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SELECT string_agg( 'ALTER INDEX IF EXISTS "' || indexname || '" RENAME TO "old_' || indexname || '";' , CHR(13)) INTO renamed_indexes
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FROM pg_indexes pg
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WHERE pg.tablename = old_tablename
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AND indexname NOT LIKE '%pkey%';
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SELECT string_agg( CASE WHEN contype = 'p' THEN -- primary key
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'ALTER INDEX IF EXISTS "' || conname || '" RENAME TO "old_' || conname || '";'
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ELSE
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'ALTER TABLE ' || old_tablename || ' RENAME CONSTRAINT "' || conname || '" TO "old_' || conname || '";'
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END
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, CHR(13)) INTO renamed_constraints
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FROM pg_catalog.pg_constraint con
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INNER JOIN pg_catalog.pg_class rel ON rel.oid = con.conrelid
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WHERE rel.relname = old_tablename;
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--======================================================================
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-- build the commands to recreate the indexes on the partitioned table
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--======================================================================
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SELECT string_agg( indexdef || ';' , CHR(13)) INTO toBeCreated_indexes
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FROM pg_indexes pg
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WHERE pg.tablename = old_tablename
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AND indexname NOT LIKE '%pkey%'
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AND indexname NOT LIKE '%' || primary_key || '%'
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AND indexdef NOT LIKE '%UNIQUE%';
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--===========================================================
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-- save the foreign key into receive_constraints variable
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--===========================================================
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SELECT string_agg(command , CHR(13) ) INTO receive_constraints
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FROM ( SELECT format('ALTER TABLE IF EXISTS "%s" ADD CONSTRAINT "%s" FOREIGN KEY ("%s") REFERENCES "%s"("%s");',
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tablename,
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tc.constraint_name,
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string_agg(distinct kcu.column_name, ','),
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ccu.table_name,
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string_agg(distinct ccu.column_name, ',')) command
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FROM information_schema.table_constraints AS tc
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JOIN information_schema.key_column_usage AS kcu
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ON tc.constraint_name = kcu.constraint_name
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JOIN information_schema.constraint_column_usage AS ccu
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ON ccu.constraint_name = tc.constraint_name
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WHERE constraint_type = 'FOREIGN KEY'
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AND tc.table_name = tablename
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GROUP BY tc.constraint_name, tc.table_name, ccu.table_name
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)x;
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--===========================================================
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-- save the triggers into receive_triggers variable
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--===========================================================
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SELECT string_agg(command , CHR(13) ) INTO receive_triggers
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FROM ( SELECT format( 'CREATE TRIGGER %s %s %s ON "%s" FOR EACH ROW %s ;',
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t1.trigger_name
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,t1.action_timing
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,t2.event_manipulation
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,t1.event_object_table
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,t1.action_statement ) as command
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FROM ( SELECT DISTINCT
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trigger_name
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,action_timing
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,event_object_table
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,action_statement
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FROM information_schema.triggers
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WHERE event_object_table = tablename
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) t1
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INNER JOIN (SELECT trigger_name, string_agg(event_manipulation, ' OR ') as event_manipulation
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FROM information_schema.triggers
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WHERE event_object_table = tablename
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GROUP BY trigger_name
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) t2 ON t1.trigger_name = t2.trigger_name
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)x;
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--===================================================================================================================
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-- save the constraints which refereces the specified tablename into toBeDeleted_constraints variable
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--===================================================================================================================
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SELECT string_agg( 'ALTER TABLE IF EXISTS "' || foreign_table || '" DROP CONSTRAINT IF EXISTS "' || constraint_name || '";' , CHR(13) ) INTO toBeDeleted_constraints
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FROM (
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select kcu.table_name as foreign_table,
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'>-' as rel,
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rel_tco.table_schema || '.' || rel_tco.table_name as primary_table,
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string_agg(kcu.column_name, ', ') as fk_columns,
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kcu.constraint_name
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from information_schema.table_constraints tco
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join information_schema.key_column_usage kcu
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on tco.constraint_schema = kcu.constraint_schema
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and tco.constraint_name = kcu.constraint_name
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join information_schema.referential_constraints rco
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on tco.constraint_schema = rco.constraint_schema
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and tco.constraint_name = rco.constraint_name
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join information_schema.table_constraints rel_tco
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on rco.unique_constraint_schema = rel_tco.constraint_schema
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and rco.unique_constraint_name = rel_tco.constraint_name
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where tco.constraint_type = 'FOREIGN KEY'
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and rel_tco.table_name = tablename
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group by kcu.table_schema,
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kcu.table_name,
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rel_tco.table_name,
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rel_tco.table_schema,
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kcu.constraint_name
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)x;
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tmp_sql = ' SELECT ''exists'' FROM pg_class WHERE relname = ''' || tablename || sequence_id || ''';';
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EXECUTE tmp_sql INTO exists_sequence;
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--RAISE NOTICE '%', COALESCE( exists_sequence, 'not exists');
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IF exists_sequence = 'exists' THEN
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EXECUTE format(' SELECT last_value FROM "%s";', tablename || sequence_id) INTO lastvalue;
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END IF;
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IF ( dropTable ) THEN
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sql_str := '--====== dropTable = true ======-- ' || CHR(13) || CHR(13) ||
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'-- drop old table with cascade ' || CHR(13) ||
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'DROP TABLE IF EXISTS ' || tablename || ' CASCADE; ' || CHR(13) ||
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'-- rename the new table to old table ' || CHR(13) ||
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'ALTER TABLE IF EXISTS ' || new_tablename || ' RENAME TO ' || tablename || ';' || CHR(13) ||
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'-- create primary key ' || CHR(13) ||
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'ALTER TABLE IF EXISTS ' || tablename || ' ADD CONSTRAINT ' || tablename || '_pkey PRIMARY KEY (' || primary_key || ',' || columnname || ');' || CHR(13) ||
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'-- create sequence ' || CHR(13) ||
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'CREATE SEQUENCE IF NOT EXISTS "' || tablename || sequence_id || '" INCREMENT 1 START ' || COALESCE(lastvalue,0) + 1 || ';' || CHR(13) ||
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'-- set id to be taken from sequence ' || CHR(13) ||
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'ALTER TABLE IF EXISTS ' || tablename || ' ALTER COLUMN ' || primary_key || ' SET DEFAULT nextval(''"' || tablename || sequence_id || '"'');' || CHR(13);
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ELSE
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sql_str := COALESCE( renamed_constraints, '') || CHR(13) ||
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COALESCE( renamed_indexes, '') || CHR(13);
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EXECUTE sql_str;
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sql_str := '--====== dropTable = false ( rename table )======-- ' || CHR(13) || CHR(13) ||
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'-- rename the current table to *_old ' || CHR(13) ||
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'ALTER TABLE IF EXISTS ' || tablename || ' RENAME TO ' || tablename || '_old; ' || CHR(13) ||
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'-- rename the new table ' || CHR(13) ||
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'ALTER TABLE IF EXISTS ' || new_tablename || ' RENAME TO ' || tablename || ';' || CHR(13) ||
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'-- create primary key ' || CHR(13) ||
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'ALTER TABLE IF EXISTS ' || tablename || ' ADD CONSTRAINT ' || tablename || '_pkey PRIMARY KEY (' || primary_key || ',' || columnname || ');' || CHR(13) ||
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'-- rename existing sequence as old ' || CHR(13) ||
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'ALTER SEQUENCE IF EXISTS "' || tablename || sequence_id || '" RENAME TO "' || tablename || '_old' || sequence_id || '";' || CHR(13) ||
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'-- create sequence ' || CHR(13) ||
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'CREATE SEQUENCE IF NOT EXISTS "' || tablename || sequence_id || '" INCREMENT 1 START ' || COALESCE(lastvalue,0) + 1 || ';' || CHR(13) ||
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'-- set id to be taken from sequence ' || CHR(13) ||
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'ALTER TABLE IF EXISTS ' || tablename || '_old' || ' ALTER COLUMN ' || primary_key || ' SET DEFAULT nextval(''"' || tablename || '_old' || sequence_id || '"'');' || CHR(13) ||
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'-- set id to be taken from sequence ' || CHR(13) ||
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'ALTER TABLE IF EXISTS ' || tablename || ' ALTER COLUMN ' || primary_key || ' SET DEFAULT nextval(''"' || tablename || sequence_id || '"'');' || CHR(13);
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END IF;
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sql_str := sql_str || COALESCE(toBeDeleted_constraints, '') || CHR(13) || COALESCE(receive_constraints, '') || CHR(13) || CHR(13) || COALESCE(receive_triggers, '');
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RAISE NOTICE '%', sql_str;
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-- execute the query
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EXECUTE sql_str;
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sql_str := COALESCE(toBeCreated_indexes, '');
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RAISE NOTICE '%', sql_str;
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EXECUTE sql_str;
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END;
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$BODY$;
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