diff --git a/packages/repository/src/__tests__/unit/repositories/legacy-juggler-bridge.unit.ts b/packages/repository/src/__tests__/unit/repositories/legacy-juggler-bridge.unit.ts
index 9b4c2664d536..e332ed9d3807 100644
--- a/packages/repository/src/__tests__/unit/repositories/legacy-juggler-bridge.unit.ts
+++ b/packages/repository/src/__tests__/unit/repositories/legacy-juggler-bridge.unit.ts
@@ -686,21 +686,52 @@ describe('DefaultCrudRepository', () => {
     expect(ok).to.be.true();
   });
 
-  it('implements Repository.execute()', async () => {
-    // Dummy implementation for execute() in datasource
-    ds.execute = (...args: unknown[]) => {
-      return Promise.resolve(args);
-    };
-    const repo = new DefaultCrudRepository(Note, ds);
-    const result = await repo.execute('query', ['arg']);
-    expect(result).to.deepEqual(['query', ['arg'], undefined]);
-  });
+  describe('Repository.execute()', () => {
+    beforeEach(() => {
+      // Dummy implementation for execute() in datasource
+      ds.execute = (...args: unknown[]) => {
+        return Promise.resolve(args);
+      };
+    });
 
-  it(`throws error when execute() not implemented by ds connector`, async () => {
-    const repo = new DefaultCrudRepository(Note, ds);
-    await expect(repo.execute('query', [])).to.be.rejectedWith(
-      'execute() must be implemented by the connector',
-    );
+    it('implements SQL variant', async () => {
+      const repo = new DefaultCrudRepository(Note, ds);
+      const result = await repo.execute('query', ['arg']);
+      expect(result).to.deepEqual(['query', ['arg']]);
+    });
+
+    it('implements MongoDB variant', async () => {
+      const repo = new DefaultCrudRepository(Note, ds);
+      const result = await repo.execute('MyCollection', 'aggregate', [
+        {$unwind: '$data'},
+        {$out: 'tempData'},
+      ]);
+      expect(result).to.deepEqual([
+        'MyCollection',
+        'aggregate',
+        [{$unwind: '$data'}, {$out: 'tempData'}],
+      ]);
+    });
+
+    it('implements a generic variant', async () => {
+      const repo = new DefaultCrudRepository(Note, ds);
+      const command = {
+        query: 'MATCH (u:User {email: {email}}) RETURN u',
+        params: {
+          email: 'alice@example.com',
+        },
+      };
+      const result = await repo.execute(command);
+      expect(result).to.deepEqual([command]);
+    });
+
+    it(`throws error when execute() not implemented by ds connector`, async () => {
+      delete ds.execute;
+      const repo = new DefaultCrudRepository(Note, ds);
+      await expect(repo.execute('query', [])).to.be.rejectedWith(
+        'execute() must be implemented by the connector',
+      );
+    });
   });
 
   it('has the property inclusionResolvers', () => {
diff --git a/packages/repository/src/repositories/legacy-juggler-bridge.ts b/packages/repository/src/repositories/legacy-juggler-bridge.ts
index 0afbb4e7146a..96a2e925d188 100644
--- a/packages/repository/src/repositories/legacy-juggler-bridge.ts
+++ b/packages/repository/src/repositories/legacy-juggler-bridge.ts
@@ -573,12 +573,95 @@ export class DefaultCrudRepository<
     return ensurePromise(this.modelClass.exists(id, options));
   }
 
-  async execute(
+  /**
+   * Execute a SQL command.
+   *
+   * **WARNING:** In general, it is always better to perform database actions
+   * through repository methods. Directly executing SQL may lead to unexpected
+   * results, corrupted data, security vulnerabilities and other issues.
+   *
+   * @example
+   *
+   * ```ts
+   * // MySQL
+   * const result = await repo.execute(
+   *   'SELECT * FROM Products WHERE size > ?',
+   *   [42]
+   * );
+   *
+   * // PostgreSQL
+   * const result = await repo.execute(
+   *   'SELECT * FROM Products WHERE size > $1',
+   *   [42]
+   * );
+   * ```
+   *
+   * @param command A parameterized SQL command or query.
+   * Check your database documentation for information on which characters to
+   * use as parameter placeholders.
+   * @param parameters List of parameter values to use.
+   * @param options Additional options, for example `transaction`.
+   * @returns A promise which resolves to the command output as returned by the
+   * database driver. The output type (data structure) is database specific and
+   * often depends on the command executed.
+   */
+  execute(
     command: Command,
     parameters: NamedParameters | PositionalParameters,
     options?: Options,
-  ): Promise<AnyObject> {
-    return ensurePromise(this.dataSource.execute(command, parameters, options));
+  ): Promise<AnyObject>;
+
+  /**
+   * Execute a MongoDB command.
+   *
+   * **WARNING:** In general, it is always better to perform database actions
+   * through repository methods. Directly executing MongoDB commands may lead
+   * to unexpected results and other issues.
+   *
+   * @example
+   *
+   * ```ts
+   * const result = await repo.execute('MyCollection', 'aggregate', [
+   *   {$lookup: {
+   *     // ...
+   *   }},
+   *   {$unwind: '$data'},
+   *   {$out: 'tempData'}
+   * ]);
+   * ```
+   *
+   * @param collectionName The name of the collection to execute the command on.
+   * @param command The command name. See
+   * [Collection API docs](http://mongodb.github.io/node-mongodb-native/3.6/api/Collection.html)
+   * for the list of commands supported by the MongoDB client.
+   * @param parameters Command parameters (arguments), as described in MongoDB API
+   * docs for individual collection methods.
+   * @returns A promise which resolves to the command output as returned by the
+   * database driver.
+   */
+  execute(
+    collectionName: string,
+    command: string,
+    ...parameters: PositionalParameters
+  ): Promise<AnyObject>;
+
+  /**
+   * Execute a raw database command using a connector that's not described
+   * by LoopBack's `execute` API yet.
+   *
+   * **WARNING:** In general, it is always better to perform database actions
+   * through repository methods. Directly executing database commands may lead
+   * to unexpected results and other issues.
+   *
+   * @param args Command and parameters, please consult your connector's
+   * documentation to learn about supported commands and their parameters.
+   * @returns A promise which resolves to the command output as returned by the
+   * database driver.
+   */
+  execute(...args: PositionalParameters): Promise<AnyObject>;
+
+  async execute(...args: PositionalParameters): Promise<AnyObject> {
+    return ensurePromise(this.dataSource.execute(...args));
   }
 
   protected toEntity<R extends T>(model: juggler.PersistedModel): R {