Show constraints on tables command
Simply query the INFORMATION_SCHEMA:
USE INFORMATION_SCHEMA;
SELECT TABLE_NAME,
COLUMN_NAME,
CONSTRAINT_NAME,
REFERENCED_TABLE_NAME,
REFERENCED_COLUMN_NAME
FROM KEY_COLUMN_USAGE
WHERE TABLE_SCHEMA = "<your_database_name>"
AND TABLE_NAME = "<your_table_name>"
AND REFERENCED_COLUMN_NAME IS NOT NULL;
afaik to make a request to information_schema
you need privileges. If you need simple list of keys you can use this command:
SHOW INDEXES IN <tablename>
The main problem with the validated answer is you'll have to parse the output to get the informations. Here is a query allowing you to get them in a more usable manner :
SELECT cols.TABLE_NAME, cols.COLUMN_NAME, cols.ORDINAL_POSITION,
cols.COLUMN_DEFAULT, cols.IS_NULLABLE, cols.DATA_TYPE,
cols.CHARACTER_MAXIMUM_LENGTH, cols.CHARACTER_OCTET_LENGTH,
cols.NUMERIC_PRECISION, cols.NUMERIC_SCALE,
cols.COLUMN_TYPE, cols.COLUMN_KEY, cols.EXTRA,
cols.COLUMN_COMMENT, refs.REFERENCED_TABLE_NAME, refs.REFERENCED_COLUMN_NAME,
cRefs.UPDATE_RULE, cRefs.DELETE_RULE,
links.TABLE_NAME, links.COLUMN_NAME,
cLinks.UPDATE_RULE, cLinks.DELETE_RULE
FROM INFORMATION_SCHEMA.`COLUMNS` as cols
LEFT JOIN INFORMATION_SCHEMA.`KEY_COLUMN_USAGE` AS refs
ON refs.TABLE_SCHEMA=cols.TABLE_SCHEMA
AND refs.REFERENCED_TABLE_SCHEMA=cols.TABLE_SCHEMA
AND refs.TABLE_NAME=cols.TABLE_NAME
AND refs.COLUMN_NAME=cols.COLUMN_NAME
LEFT JOIN INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS AS cRefs
ON cRefs.CONSTRAINT_SCHEMA=cols.TABLE_SCHEMA
AND cRefs.CONSTRAINT_NAME=refs.CONSTRAINT_NAME
LEFT JOIN INFORMATION_SCHEMA.`KEY_COLUMN_USAGE` AS links
ON links.TABLE_SCHEMA=cols.TABLE_SCHEMA
AND links.REFERENCED_TABLE_SCHEMA=cols.TABLE_SCHEMA
AND links.REFERENCED_TABLE_NAME=cols.TABLE_NAME
AND links.REFERENCED_COLUMN_NAME=cols.COLUMN_NAME
LEFT JOIN INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS AS cLinks
ON cLinks.CONSTRAINT_SCHEMA=cols.TABLE_SCHEMA
AND cLinks.CONSTRAINT_NAME=links.CONSTRAINT_NAME
WHERE cols.TABLE_SCHEMA=DATABASE()
AND cols.TABLE_NAME="table"
I use
SHOW CREATE TABLE mytable;
This shows you the SQL statement necessary to receate mytable
in its current form. You can see all the columns and their types (like DESC
) but it also shows you constraint information (and table type, charset, etc.).