Use system catalogues instead of 'information_schema'

obsidiansystems · Sep 12, 2023 · 561a3db · 561a3db
1 parent b1b06fd
commit 561a3db
Showing 1 changed file with 27 additions and 22 deletions.
diff --git a/src/Database/Beam/AutoMigrate/Postgres.hs b/src/Database/Beam/AutoMigrate/Postgres.hs
@@ -110,11 +110,16 @@ defaultsQ :: Pg.Query
 defaultsQ =
  fromString $
  unlines
- [ "SELECT col.table_name::text, col.column_name::text, col.column_default::text, col.data_type::text ",
- "FROM information_schema.columns col ",
- "WHERE col.column_default IS NOT NULL ",
- "AND col.table_schema NOT IN('information_schema', 'pg_catalog') ",
- "ORDER BY col.table_name"
+ [ "SELECT"
+ , " a.attrelid::regclass::text AS \"table_name\""
+ , " , a.attname::text AS \"column_name\""
+ , " , pg_get_expr(d.adbin, d.adrelid) AS \"column_default\""
+ , " , format_type(a.atttypid, NULL) AS \"data_type\""
+ , "FROM pg_catalog.pg_attribute a"
+ , "JOIN pg_catalog.pg_attrdef d ON (a.attrelid, a.attnum) = (d.adrelid, d.adnum)"
+ , "WHERE NOT a.attisdropped -- no dropped (dead) columns"
+ , " AND a.attnum > 0 -- no system columns"
+ , "ORDER BY \"table_name\", \"column_name\""
  ]
 
 -- | Get information about columns for this table. Due to the fact this is a query executed for /each/
@@ -147,23 +152,23 @@ foreignKeysQ :: Pg.Query
 foreignKeysQ =
  fromString $
  unlines
- [ "SELECT kcu.table_name::text as foreign_table,",
-  "  rel_kcu.table_name::text as primary_table,",
-  "  array_agg(kcu.column_name::text ORDER BY kcu.position_in_unique_constraint)::text[] as fk_columns,",
-  "  array_agg(rel_kcu.column_name::text ORDER BY rel_kcu.ordinal_position)::text[] as pk_columns,",
-  "  kcu.constraint_name as cname",
-  "FROM information_schema.table_constraints tco",
-  "JOIN information_schema.key_column_usage kcu",
-  " on tco.constraint_schema = kcu.constraint_schema",
-  " and tco.constraint_name = kcu.constraint_name",
-  "JOIN information_schema.referential_constraints rco",
-  " on tco.constraint_schema = rco.constraint_schema",
-  " and tco.constraint_name = rco.constraint_name",
-  "JOIN information_schema.key_column_usage rel_kcu",
-  " on rco.unique_constraint_schema = rel_kcu.constraint_schema",
-  " and rco.unique_constraint_name = rel_kcu.constraint_name",
-  " and kcu.ordinal_position = rel_kcu.ordinal_position",
-  "GROUP BY foreign_table, primary_table, cname"
+ [ "SELECT"
+ , " conrelid::regclass::text as \"foreign_table\""
+ , " , confrelid::regclass::text as \"primary_table\""
+ , " , ARRAY_AGG(col.attname::text ORDER BY u.attposition)::text[] AS \"fk_columns\""
+ , " , ARRAY_AGG(f_col.attname::text ORDER BY f_u.attposition)::text[] AS \"pk_columns\""
+ , " , conname::text as \"cname\""
+ , "FROM pg_catalog.pg_constraint c"
+ , "LEFT JOIN LATERAL UNNEST(c.conkey) WITH ORDINALITY AS u(attnum, attposition) ON TRUE"
+ , "LEFT JOIN LATERAL UNNEST(c.confkey) WITH ORDINALITY AS f_u(attnum, attposition) ON f_u.attposition = u.attposition"
+ , "JOIN pg_class tbl ON tbl.oid = c.conrelid"
+ , "JOIN pg_namespace sch ON sch.oid = tbl.relnamespace"
+ , "JOIN pg_attribute col ON (col.attrelid = tbl.oid AND col.attnum = u.attnum)"
+ , "JOIN pg_class f_tbl ON f_tbl.oid = c.confrelid"
+ , "JOIN pg_namespace f_sch ON f_sch.oid = f_tbl.relnamespace"
+ , "JOIN pg_attribute f_col ON (f_col.attrelid = f_tbl.oid AND f_col.attnum = f_u.attnum)"
+ , "WHERE contype = 'f'"
+ , "GROUP BY \"foreign_table\", \"primary_table\", \"cname\""
  ]
 
 -- | Return /all other constraints that are not FKs/ (i.e. 'PRIMARY KEY', 'UNIQUE', etc) for all the tables.