feat(lib/columns): add is_unique to retrieve & update

Author: soedirgo

src/lib/PostgresMetaColumns.ts

@@ -163,6 +163,7 @@ COMMIT;`
       is_identity,
       identity_generation,
       is_nullable,
+      is_unique,
       comment,
     }: {
       name?: string
@@ -173,6 +174,7 @@ COMMIT;`
       is_identity?: boolean
       identity_generation?: 'BY DEFAULT' | 'ALWAYS'
       is_nullable?: boolean
+      is_unique?: boolean
       comment?: string
     }
   ): Promise<PostgresMetaResult<PostgresColumn>> {
@@ -245,6 +247,32 @@ COMMIT;`
             old!.name
           )} SET NOT NULL;`
     }
+    let isUniqueSql = ''
+    if (old!.is_unique === true && is_unique === false) {
+      isUniqueSql = `
+DO $$
+DECLARE
+  r record;
+BEGIN
+  FOR r IN
+    SELECT conname FROM pg_constraint WHERE
+      contype = 'u'
+      AND cardinality(conkey) = 1
+      AND conrelid = ${literal(old!.table_id)}
+      AND conkey[1] = ${literal(old!.ordinal_position)}
+  LOOP
+    EXECUTE ${literal(
+      `ALTER TABLE ${ident(old!.schema)}.${ident(old!.table)} DROP CONSTRAINT `
+    )} || quote_ident(r.conname);
+  END LOOP;
+END
+$$;
+`
+    } else if (old!.is_unique === false && is_unique === true) {
+      isUniqueSql = `ALTER TABLE ${ident(old!.schema)}.${ident(old!.table)} ADD UNIQUE (${ident(
+        old!.name
+      )});`
+    }
     const commentSql =
       comment === undefined
         ? ''
@@ -262,6 +290,7 @@ BEGIN;
   ${typeSql}
   ${defaultValueSql}
   ${identitySql}
+  ${isUniqueSql}
   ${commentSql}
   ${nameSql}
 COMMIT;`

src/lib/sql/columns.sql

@@ -26,32 +26,22 @@ SELECT
     END
   END AS data_type,
   COALESCE(bt.typname, t.typname) AS format,
-  CASE
-    WHEN a.attidentity IN ('a', 'd') THEN TRUE
-    ELSE FALSE
-  END AS is_identity,
+  a.attidentity IN ('a', 'd') AS is_identity,
   CASE
     a.attidentity
     WHEN 'a' THEN 'ALWAYS'
     WHEN 'd' THEN 'BY DEFAULT'
     ELSE NULL
   END AS identity_generation,
-  CASE
-    WHEN a.attnotnull
-    OR t.typtype = 'd'
-    AND t.typnotnull THEN FALSE
-    ELSE TRUE
-  END AS is_nullable,
-  CASE
-    WHEN (
-      c.relkind IN ('r', 'p')
-    )
-    OR (
-      c.relkind IN ('v', 'f')
-    )
-    AND pg_column_is_updatable(c.oid, a.attnum, FALSE) THEN TRUE
-    ELSE FALSE
-  END AS is_updatable,
+  NOT (
+    a.attnotnull
+    OR t.typtype = 'd' AND t.typnotnull
+  ) AS is_nullable,
+  (
+    c.relkind IN ('r', 'p')
+    OR c.relkind IN ('v', 'f') AND pg_column_is_updatable(c.oid, a.attnum, FALSE)
+  ) AS is_updatable,
+  uniques.table_id IS NOT NULL AS is_unique,
   array_to_json(
     array(
       SELECT
@@ -82,6 +72,13 @@ FROM
     JOIN pg_namespace nbt ON bt.typnamespace = nbt.oid
   ) ON t.typtype = 'd'
   AND t.typbasetype = bt.oid
+  LEFT JOIN (
+    SELECT
+      conrelid AS table_id,
+      conkey[1] AS ordinal_position
+    FROM pg_catalog.pg_constraint
+    WHERE contype = 'u' AND cardinality(conkey) = 1
+  ) AS uniques ON uniques.table_id = c.oid AND uniques.ordinal_position = a.attnum
 WHERE
   NOT pg_is_other_temp_schema(nc.oid)
   AND a.attnum > 0

src/lib/types.ts

@@ -32,6 +32,7 @@ export const postgresColumnSchema = Type.Object({
   ]),
   is_nullable: Type.Boolean(),
   is_updatable: Type.Boolean(),
+  is_unique: Type.Boolean(),
   enums: Type.Array(Type.Unknown()),
   comment: Type.Union([Type.String(), Type.Null()]),
 })