types: support no-SQL styles of `ds.execute`

Signed-off-by: Miroslav Bajtoš <mbajtoss@gmail.com>

types/__test__.ts

@@ -88,3 +88,30 @@ const db = new DataSource('db', {connector: 'memory'});
     await ctx.Model.expire('key', 100);
   });
 });
+
+//-------
+// DataSource supports different `execute` styles
+//-------
+(async function () {
+  // SQL style
+  const tx = await db.beginTransaction();
+  await db.execute('SELECT * FROM Product WHERE count > ?', [10], {
+    transaction: tx,
+  });
+  await tx.commit();
+
+  // MongoDB style
+  await db.execute('MyCollection', 'aggregate', [
+    {$lookup: { /* ... */ }},
+    {$unwind: '$data'},
+    {$out: 'tempData'}
+  ]);
+
+  // Neo4J style
+  await db.execute({
+    query: 'MATCH (u:User {email: {email}}) RETURN u',
+    params: {
+      email: 'alice@example.com',
+    },
+  });
+});

types/datasource.d.ts

@@ -300,12 +300,94 @@ export declare class DataSource extends EventEmitter {
   ping(callback: Callback): void;
 
   // Only promise variant, callback is intentionally not supported.
+
+  /**
+   * 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 db.execute(
+   *   'SELECT * FROM Products WHERE size > ?',
+   *   [42]
+   * );
+   *
+   * // PostgreSQL
+   * const result = await db.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: string | object,
-    args?: any[] | object,
+    parameters?: any[] | object,
     options?: Options,
   ): Promise<any>;
 
+  /**
+   * 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 db.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: any[],
+  ): Promise<any>;
+
+  /**
+   * 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: any[]): Promise<any>;
+
   /**
    * Begin a new transaction.
    *