How do I automatically detect and delete duplicate Foreign-key constraints in Postgresql

My Postgresql database has a large number of duplicate foreign key constraints on tables for example

"fkb43bb0b712b68565" FOREIGN KEY (owner_id)开发者_StackOverflow社区 REFERENCES usr(id)
"fkb43bb0b71b63ed43" FOREIGN KEY (owner_id) REFERENCES usr(id)

They're doing the same thing but have unique names.

How can I automatically detect and delete such duplicates?

Thanks

J

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SELECT
    pc.conname as constraint_name, 
    --conrelid as child_table_id,   
    pclsc.relname as child_table,
    --pc.conkey as child_column_id,
    pac.attname as child_column,
    --confrelid as parent_table_id,
    pclsp.relname as parent_table,
    --pc.confkey as parent_column_id,
    pap.attname as parent_column,   
    nspname as schema_name
FROM 
    (
    SELECT
         connamespace,conname, unnest(conkey) as "conkey", unnest(confkey)
          as "confkey" , conrelid, confrelid, contype
     FROM
        pg_constraint
    ) pc
    JOIN pg_namespace pn ON pc.connamespace = pn.oid
    -- and pn.nspname = 'panmydesk4400'
    JOIN pg_class pclsc ON pc.conrelid = pclsc.oid
    JOIN pg_class pclsp ON      pc.confrelid = pclsp.oid
    JOIN pg_attribute pac ON pc.conkey = pac.attnum    and pac.attrelid =       pclsc.oid
    JOIN pg_attribute pap ON pc.confkey = pap.attnum and pap.attrelid = pclsp.oid

ORDER BY pclsc.relname

above query will return all the foreign key constraint from that u simply delete the duplicate entries.

Note : if you remove the comments from above query you can view the relID and ColID and the query should work for all the schema in the database

---

SELECT
    array_agg(pc.conname) as duplicated_constraints, 
    pclsc.relname as child_table,
    pac.attname as child_column,
    pclsp.relname as parent_table,
    pap.attname as parent_column,   
    nspname as schema_name
FROM 
    (
    SELECT
     connamespace,conname, unnest(conkey) as "conkey", unnest(confkey)
      as "confkey" , conrelid, confrelid, contype
     FROM
        pg_constraint
    ) pc
    JOIN pg_namespace pn ON pc.connamespace = pn.oid
    JOIN pg_class pclsc ON pc.conrelid = pclsc.oid
    JOIN pg_class pclsp ON pc.confrelid = pclsp.oid
    JOIN pg_attribute pac ON pc.conkey = pac.attnum and pac.attrelid = pclsc.oid
    JOIN pg_attribute pap ON pc.confkey = pap.attnum and pap.attrelid = pclsp.oid
GROUP BY child_table, child_column, parent_table, parent_column, schema_name HAVING COUNT(*)>1
ORDER BY child_table, child_column

will list only duplicated foreign key constraints in Postgresql

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Constraints are stored in pg_constraint, just query this view to find double constraints.