How do I produce CREATE TABLE SQL script to recreate a redshift table


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3 months ago by

1 Answer


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3 months ago by
The answer is here: https://discourse.snowplowanalytics.com/t/generating-redshift-ddl-create-statements-for-tables-that-already-exist/556
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
create an admin schema:
CREATE SCHEMA admin;
COMMIT;
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
analyse the tables:
CREATE OR REPLACE VIEW admin.v_generate_tbl_ddl
AS
SELECT
REGEXP_REPLACE (schemaname, '^zzzzzzzz', '') AS schemaname
,REGEXP_REPLACE (tablename, '^zzzzzzzz', '') AS tablename
,seq
,ddl
FROM
(
SELECT
schemaname
,tablename
,seq
,ddl
FROM
(
--DROP TABLE
SELECT
n.nspname AS schemaname
,c.relname AS tablename
,0 AS seq
,'--DROP TABLE "' + n.nspname + '"."' + c.relname + '";' AS ddl
FROM pg_namespace AS n
INNER JOIN pg_class AS c ON n.oid = c.relnamespace
WHERE c.relkind = 'r'
--CREATE TABLE
UNION SELECT
n.nspname AS schemaname
,c.relname AS tablename
,2 AS seq
,'CREATE TABLE IF NOT EXISTS "' + n.nspname + '"."' + c.relname + '"' AS ddl
FROM pg_namespace AS n
INNER JOIN pg_class AS c ON n.oid = c.relnamespace
WHERE c.relkind = 'r'
--OPEN PAREN COLUMN LIST
UNION SELECT n.nspname AS schemaname, c.relname AS tablename, 5 AS seq, '(' AS ddl
FROM pg_namespace AS n
INNER JOIN pg_class AS c ON n.oid = c.relnamespace
WHERE c.relkind = 'r'
--COLUMN LIST
UNION SELECT
schemaname
,tablename
,seq
,'\t' + col_delim + col_name + ' ' + col_datatype + ' ' + col_nullable + ' ' + col_default + ' ' + col_encoding AS ddl
FROM
(
SELECT
n.nspname AS schemaname
,c.relname AS tablename
,100000000 + a.attnum AS seq
,CASE WHEN a.attnum > 1 THEN ',' ELSE '' END AS col_delim
,'"' + a.attname + '"' AS col_name
,CASE WHEN STRPOS(UPPER(format_type(a.atttypid, a.atttypmod)), 'CHARACTER VARYING') > 0
THEN REPLACE(UPPER(format_type(a.atttypid, a.atttypmod)), 'CHARACTER VARYING', 'VARCHAR')
WHEN STRPOS(UPPER(format_type(a.atttypid, a.atttypmod)), 'CHARACTER') > 0
THEN REPLACE(UPPER(format_type(a.atttypid, a.atttypmod)), 'CHARACTER', 'CHAR')
ELSE UPPER(format_type(a.atttypid, a.atttypmod))
END AS col_datatype
,CASE WHEN format_encoding((a.attencodingtype)::integer) = 'none'
THEN ''
ELSE 'ENCODE ' + format_encoding((a.attencodingtype)::integer)
END AS col_encoding
,CASE WHEN a.atthasdef IS TRUE THEN 'DEFAULT ' + adef.adsrc ELSE '' END AS col_default
,CASE WHEN a.attnotnull IS TRUE THEN 'NOT NULL' ELSE '' END AS col_nullable
FROM pg_namespace AS n
INNER JOIN pg_class AS c ON n.oid = c.relnamespace
INNER JOIN pg_attribute AS a ON c.oid = a.attrelid
LEFT OUTER JOIN pg_attrdef AS adef ON a.attrelid = adef.adrelid AND a.attnum = adef.adnum
WHERE c.relkind = 'r'
AND a.attnum > 0
ORDER BY a.attnum
)
--CONSTRAINT LIST
UNION (SELECT
n.nspname AS schemaname
,c.relname AS tablename
,200000000 + CAST(con.oid AS INT) AS seq
,'\t,' + pg_get_constraintdef(con.oid) AS ddl
FROM pg_constraint AS con
INNER JOIN pg_class AS c ON c.relnamespace = con.connamespace AND c.oid = con.conrelid
INNER JOIN pg_namespace AS n ON n.oid = c.relnamespace
WHERE c.relkind = 'r' AND pg_get_constraintdef(con.oid) NOT LIKE 'FOREIGN KEY%'
ORDER BY seq)
--CLOSE PAREN COLUMN LIST
UNION SELECT n.nspname AS schemaname, c.relname AS tablename, 299999999 AS seq, ')' AS ddl
FROM pg_namespace AS n
INNER JOIN pg_class AS c ON n.oid = c.relnamespace
WHERE c.relkind = 'r'
--BACKUP
UNION SELECT
n.nspname AS schemaname
,c.relname AS tablename
,300000000 AS seq
,'BACKUP NO' as ddl
FROM pg_namespace AS n
INNER JOIN pg_class AS c ON n.oid = c.relnamespace
INNER JOIN (SELECT
SPLIT_PART(key,'_',5) id
FROM pg_conf
WHERE key LIKE 'pg_class_backup_%'
AND SPLIT_PART(key,'_',4) = (SELECT
oid
FROM pg_database
WHERE datname = current_database())) t ON t.id=c.oid
WHERE c.relkind = 'r'
--BACKUP WARNING
UNION SELECT
n.nspname AS schemaname
,c.relname AS tablename
,1 AS seq
,'--WARNING: This DDL inherited the BACKUP NO property from the source table' as ddl
FROM pg_namespace AS n
INNER JOIN pg_class AS c ON n.oid = c.relnamespace
INNER JOIN (SELECT
SPLIT_PART(key,'_',5) id
FROM pg_conf
WHERE key LIKE 'pg_class_backup_%'
AND SPLIT_PART(key,'_',4) = (SELECT
oid
FROM pg_database
WHERE datname = current_database())) t ON t.id=c.oid
WHERE c.relkind = 'r'
--DISTSTYLE
UNION SELECT
n.nspname AS schemaname
,c.relname AS tablename
,300000001 AS seq
,CASE WHEN c.reldiststyle = 0 THEN 'DISTSTYLE EVEN'
WHEN c.reldiststyle = 1 THEN 'DISTSTYLE KEY'
WHEN c.reldiststyle = 8 THEN 'DISTSTYLE ALL'
ELSE '<<Error - UNKNOWN DISTSTYLE>>'
END AS ddl
FROM pg_namespace AS n
INNER JOIN pg_class AS c ON n.oid = c.relnamespace
WHERE c.relkind = 'r'
--DISTKEY COLUMNS
UNION SELECT
n.nspname AS schemaname
,c.relname AS tablename
,400000000 + a.attnum AS seq
,'DISTKEY ("' + a.attname + '")' AS ddl
FROM pg_namespace AS n
INNER JOIN pg_class AS c ON n.oid = c.relnamespace
INNER JOIN pg_attribute AS a ON c.oid = a.attrelid
WHERE c.relkind = 'r'
AND a.attisdistkey IS TRUE
AND a.attnum > 0
--SORTKEY COLUMNS
UNION select schemaname, tablename, seq,
case when min_sort <0 then 'INTERLEAVED SORTKEY (' else 'SORTKEY (' end as ddl
from (SELECT
n.nspname AS schemaname
,c.relname AS tablename
,499999999 AS seq
,min(attsortkeyord) min_sort FROM pg_namespace AS n
INNER JOIN pg_class AS c ON n.oid = c.relnamespace
INNER JOIN pg_attribute AS a ON c.oid = a.attrelid
WHERE c.relkind = 'r'
AND abs(a.attsortkeyord) > 0
AND a.attnum > 0
group by 1,2,3 )
UNION (SELECT
n.nspname AS schemaname
,c.relname AS tablename
,500000000 + abs(a.attsortkeyord) AS seq
,CASE WHEN abs(a.attsortkeyord) = 1
THEN '\t"' + a.attname + '"'
ELSE '\t, "' + a.attname + '"'
END AS ddl
FROM pg_namespace AS n
INNER JOIN pg_class AS c ON n.oid = c.relnamespace
INNER JOIN pg_attribute AS a ON c.oid = a.attrelid
WHERE c.relkind = 'r'
AND abs(a.attsortkeyord) > 0
AND a.attnum > 0
ORDER BY abs(a.attsortkeyord))
UNION SELECT
n.nspname AS schemaname
,c.relname AS tablename
,599999999 AS seq
,'\t)' AS ddl
FROM pg_namespace AS n
INNER JOIN pg_class AS c ON n.oid = c.relnamespace
INNER JOIN pg_attribute AS a ON c.oid = a.attrelid
WHERE c.relkind = 'r'
AND abs(a.attsortkeyord) > 0
AND a.attnum > 0
--END SEMICOLON
UNION SELECT n.nspname AS schemaname, c.relname AS tablename, 600000000 AS seq, ';' AS ddl
FROM pg_namespace AS n
INNER JOIN pg_class AS c ON n.oid = c.relnamespace
WHERE c.relkind = 'r' )
UNION (
SELECT 'zzzzzzzz' || n.nspname AS schemaname,
'zzzzzzzz' || c.relname AS tablename,
700000000 + CAST(con.oid AS INT) AS seq,
'ALTER TABLE ' + n.nspname + '.' + c.relname + ' ADD ' + pg_get_constraintdef(con.oid)::VARCHAR(1024) + ';' AS ddl
FROM pg_constraint AS con
INNER JOIN pg_class AS c
ON c.relnamespace = con.connamespace
AND c.oid = con.conrelid
INNER JOIN pg_namespace AS n ON n.oid = c.relnamespace
WHERE c.relkind = 'r'
AND con.contype = 'f'
ORDER BY seq
)
ORDER BY schemaname, tablename, seq
)
;
commit;
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
then finally get the SQL for one table:
select ddl
from admin.v_generate_tbl_ddl
where schemaname = 'public'
and tablename = 'xxxxxxxxxxx';

or all tables:

select ddl
from admin.v_generate_tbl_ddl
where schemaname = 'public';




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