MySQL optimisation (knex#138)

365talents · Mar 1, 2023 · c50b30d · c50b30d
1 parent 9712422
commit c50b30d
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Showing 2 changed files with 38 additions and 28 deletions.
diff --git a/lib/dialects/mysql.ts b/lib/dialects/mysql.ts
@@ -289,35 +289,31 @@ export default class MySQL implements SchemaInspector {
   // ===============================================================================================
 
   async foreignKeys(table?: string) {
-    const result = await this.knex.raw<[ForeignKey[]]>(
-      `
-      SELECT DISTINCT
-        rc.TABLE_NAME AS 'table',
-        kcu.COLUMN_NAME AS 'column',
-        rc.REFERENCED_TABLE_NAME AS 'foreign_key_table',
-        kcu.REFERENCED_COLUMN_NAME AS 'foreign_key_column',
-        rc.CONSTRAINT_NAME AS 'constraint_name',
-        rc.UPDATE_RULE AS on_update,
-        rc.DELETE_RULE AS on_delete
-      FROM
-        information_schema.referential_constraints AS rc
-      JOIN information_schema.key_column_usage AS kcu ON
-        rc.CONSTRAINT_NAME = kcu.CONSTRAINT_NAME
-        AND kcu.CONSTRAINT_SCHEMA = rc.CONSTRAINT_SCHEMA
-      WHERE
-        rc.CONSTRAINT_SCHEMA = ?;
-    `,
-      [this.knex.client.database()]
-    );
-
-    // Mapping casts "RowDataPacket" object from mysql to plain JS object
-
+    const query = this.knex
+      .select(
+        `rc.TABLE_NAME AS table`,
+        `kcu.COLUMN_NAME AS column`,
+        `rc.REFERENCED_TABLE_NAME AS foreign_key_table`,
+        `kcu.REFERENCED_COLUMN_NAME AS foreign_key_column`,
+        `rc.CONSTRAINT_NAME AS constraint_name`,
+        `rc.UPDATE_RULE AS on_update`,
+        `rc.DELETE_RULE AS on_delete`
+      )
+      .from(`information_schema.referential_constraints AS rc`)
+      .leftJoin(`information_schema.key_column_usage AS kcu `, function () {
+        this.on(`rc.CONSTRAINT_NAME`, `=`, `kcu.CONSTRAINT_NAME`).andOn(
+          `kcu.CONSTRAINT_SCHEMA`,
+          `=`,
+          `rc.CONSTRAINT_SCHEMA`
+        );
+      })
+      .where({
+        'rc.CONSTRAINT_SCHEMA': this.knex.client.database(),
+      });
     if (table) {
-      return result?.[0]
-        ?.filter((row) => row.table === table)
-        .map((row) => ({ ...row }));
+      query.andWhere({ 'rc.TABLE_NAME': table });
     }
-
-    return result?.[0].map((row) => ({ ...row }));
+    const result: ForeignKey[] = await query;
+    return result;
   }
 }
diff --git a/test/mysql.spec.ts b/test/mysql.spec.ts
@@ -609,5 +609,19 @@ describe('mysql', () => {
     it('filters based on table param', async () => {
       expect(await inspector.foreignKeys('teams')).to.deep.equal([]);
     });
+
+    it('filters valid tables based on param', async () => {
+      expect(await inspector.foreignKeys('users')).to.deep.equal([
+        {
+          table: 'users',
+          column: 'team_id',
+          foreign_key_table: 'teams',
+          foreign_key_column: 'id',
+          constraint_name: 'fk_team_id',
+          on_delete: 'CASCADE',
+          on_update: 'CASCADE',
+        },
+      ]);
+    });
   });
 });