# SQL - Data Dictionary
*Source: [sql_scripts/data_dict_dump.sql at main · DataResearchLabs/sql_scripts (github.com)](https://github.com/DataResearchLabs/sql_scripts/blob/main/postgresql/data_dictionary/data_dict_dump.sql)*
See Also: [[Creating a data dictionary with SQL]]
```SQL
------------------------------------------------------------------------------------
-- Data Dictionary Dump:
-- This SQL script will dump table, column, key, and description design related
-- metadata so that you can copy-paste or export to Excel as a Data Dictionary.
------------------------------------------------------------------------------------
-- Platform: PostgreSQL
-- Author: DataResearchLabs
-- GitHub: https://github.com/DataResearchLabs/sql_scripts
-- YouTube Tutorials: https://www.youtube.com/channel/UCQciXv3xaBykeUFc04GxSXA
----------------------------------------------------------------------------------
WITH vars
AS (
SELECT
'public' AS v_SchemaName -- Set to the schema whose tables you want in the Data Dictionary
, 'NO' AS v_TablesOnly -- YES=Limit To Tables only; NO=Include views too
)
, baseTbl
AS (
SELECT table_schema AS SchemaName
, table_catalog
, table_type, table_name, table_schema
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = (SELECT v_SchemaName FROM vars)
AND ( (TABLE_TYPE = 'BASE TABLE')
OR ((SELECT v_TablesOnly FROM vars) = 'NO')
)
)
, metadata
AS (
SELECT
bt.SchemaName AS schema_nm
, bt.table_name AS table_nm
, CASE WHEN bt.TABLE_TYPE = 'BASE TABLE' THEN 'TBL'
WHEN bt.TABLE_TYPE = 'VIEW' THEN 'VW'
ELSE 'UK'
END AS obj_typ
, tut.ordinal_position AS ord_pos
, tut.column_name AS column_nm
, CONCAT(COALESCE(tut.data_type, 'unknown'),
CASE WHEN tut.data_type IN('varchar','char') THEN CONCAT('(', CAST(tut.CHARACTER_MAXIMUM_LENGTH AS varchar(10)), ')')
WHEN tut.data_type IN('date','time') THEN CONCAT('(3)')
WHEN tut.data_type = 'datetime' THEN CONCAT('(8)')
WHEN tut.data_type = 'timestamp' THEN CONCAT('(4)')
WHEN tut.data_type in('bigint','integer','smallint') THEN CONCAT('(', CAST(tut.NUMERIC_PRECISION AS varchar(10)), ')')
WHEN tut.data_type = 'decimal' THEN CONCAT('(', CAST(tut.NUMERIC_PRECISION AS varchar(10)), ',', CAST(tut.NUMERIC_SCALE AS varchar(10)), ')')
WHEN tut.CHARACTER_MAXIMUM_LENGTH IS NOT NULL THEN CONCAT('(', CAST(tut.CHARACTER_MAXIMUM_LENGTH AS varchar(10)), ')')
WHEN tut.DATETIME_PRECISION IS NOT NULL THEN CONCAT('(', CAST(tut.DATETIME_PRECISION AS varchar(10)), ')')
WHEN tut.NUMERIC_PRECISION IS NOT NULL
AND tut.NUMERIC_SCALE IS NULL THEN CONCAT('(', CAST(tut.NUMERIC_PRECISION AS varchar(10)), ')')
WHEN tut.NUMERIC_PRECISION IS NOT NULL
AND tut.NUMERIC_SCALE IS NOT NULL THEN CONCAT('(', CAST(tut.NUMERIC_PRECISION AS varchar(10)), ',', CAST(tut.NUMERIC_SCALE AS varchar(10)), ')')
ELSE ''
END ) AS data_typ
, CASE WHEN tut.IS_NULLABLE = 'YES' THEN 'NULL' ELSE 'NOT NULL' END AS nullable
FROM INFORMATION_SCHEMA.COLUMNS tut
INNER JOIN baseTbl bt ON bt.table_catalog = tut.TABLE_CATALOG AND bt.table_name = tut.table_name
)
, meta_for_keys
AS (
SELECT schema_nm, table_nm, column_nm
, STRING_AGG(is_key, ',' ORDER BY is_key) AS is_key
FROM (
SELECT cons.TABLE_SCHEMA AS schema_nm
, cons.TABLE_NAME AS table_nm
, kcu.COLUMN_NAME AS column_nm
, CASE WHEN cons.constraint_type = 'PRIMARY KEY' THEN 'PK'
WHEN cons.constraint_type = 'UNIQUE' THEN 'UK'
WHEN cons.constraint_type = 'FOREIGN KEY' THEN 'FK'
ELSE 'X'
END AS is_key
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS cons
INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE kcu
ON cons.TABLE_SCHEMA = kcu.TABLE_SCHEMA
AND cons.TABLE_NAME = kcu.TABLE_NAME
AND cons.CONSTRAINT_NAME = kcu.CONSTRAINT_NAME
WHERE cons.table_schema = (SELECT v_SchemaName FROM vars)
AND cons.table_name IN(SELECT DISTINCT table_name FROM baseTbl)
AND cons.constraint_type IN('PRIMARY KEY','FOREIGN KEY','UNIQUE')
GROUP BY cons.TABLE_SCHEMA, cons.TABLE_NAME, kcu.COLUMN_NAME, cons.constraint_type
) t
GROUP BY schema_nm, table_nm, column_nm
)
, col_comm
AS (
SELECT c.TABLE_SCHEMA AS schema_nm
, c.TABLE_NAME AS table_nm
, c.COLUMN_NAME AS column_nm
, pgd.DESCRIPTION AS column_descr
FROM pg_catalog.pg_statio_all_tables AS st
INNER JOIN pg_catalog.PG_DESCRIPTION AS pgd ON pgd.objoid = st.relid
INNER JOIN INFORMATION_SCHEMA.COLUMNS AS c ON pgd.objsubid = c.ordinal_position
AND c.table_schema = st.schemaname
AND c.table_name = st.relname
WHERE c.table_schema = (SELECT v_SchemaName FROM vars)
AND c.table_name IN(SELECT DISTINCT table_name FROM baseTbl)
)
SELECT md.SCHEMA_NM, md.TABLE_NM, md.OBJ_TYP
, md.ORD_POS AS ord
, COALESCE(pk.is_key, ' ') AS is_key
, md.COLUMN_NM, md.DATA_TYP, md.NULLABLE, c.column_descr
FROM metadata md
LEFT JOIN meta_for_keys pk ON pk.SCHEMA_NM = md.SCHEMA_NM AND pk.TABLE_NM = md.TABLE_NM AND pk.COLUMN_NM = md.COLUMN_NM
LEFT JOIN col_comm c ON c.SCHEMA_NM = md.SCHEMA_NM AND c.TABLE_NM = md.TABLE_NM AND c.COLUMN_NM = md.COLUMN_NM
ORDER BY md.SCHEMA_NM, md.TABLE_NM, md.ORD_POS
```
***
## Appendix: Links
- [[2-Areas/Code/_README|Code]]
- [[SQL]]
- [[Databases]]
- [[PostgreSQL]]
- [[Development]]
*Backlinks:*
```dataview
list from [[SQL - DataDictionary]] AND -"Changelog"
```