# Executing Queries

Use a [DataSource](https://docs.wirebootstrap.com/wirebootstrap/reference/wire.data/wire.data.datasource) object to execute queries in a data service and retrieve the results.

## ExecAsync

The data source `execAsync` method returns a [deferred jQuery promise](https://api.jquery.com/deferred.promise).  Use this asynchronous method to execute the query in the data service.

```javascript
const accountService = new wire.data.DataSource("custom", {
    ServiceRoot: "./account"
});

const query = wire.data.select()
    .from("Users")
    .where().eq("Active", true);
    
const users = await accountService.execAsync(query);
```

### Short-Hand

Queries can also be executed directly from both a [TableQuery](https://docs.wirebootstrap.com/wirebootstrap/creating-queries/select-queries) and [StoredProcedure](https://docs.wirebootstrap.com/wirebootstrap/creating-queries/stored-procedures) object using the `execAsync` method which takes the data source as a parameter.

```javascript
...
const users = await wire.data.select()
    .from("Users")
    .where().eq("Active", true)
    .execAsync(accountService);
```

### TypeScript

TypeScript requires a method to return a specific type.  To cast the response from the `execAsync` method to a type use the `as undefined` pattern.

In the example below,  the results can be cast directly into an array of `User` class objects by first casting them as `undefined`.

```typescript
const accountService = new wire.data.DataSource("custom", {
    ServiceRoot: "./account"
});

const query = wire.data.select()
    .from("Users")
    .where().eq("Active", true);
    
const users = await accountService.execAsync(query) as undefined as Array<User>;
```

### DataTables

The format of asynchronous results depends on how the data connector returns the data.  In the example above, the [Custom Data Connector](https://docs.wirebootstrap.com/wirebootstrap/connecting-to-data/data-connectors/custom-web-services) results are returned as an array of plain JavaScript objects containing the user data.

An instance of [WireBootstrap's DataTable](https://docs.wirebootstrap.com/wirebootstrap/working-with-datatables/datatables) can also be created from the array in order to work with the data locally.

```typescript
const users = await accountService.execAsync(query) as undefined as Array<User>

const userTable = new wire.data.DataTable(users);
```

In the example below, the [Query Service](https://docs.wirebootstrap.com/query-service) service provider returns a data table automatically.

```typescript
const accountService = new wire.data.DataSource("sql", {
    ServiceRoot: "./account"
});

const query = wire.data.select()
    .from("Users")
    .where().eq("Active", true);
    
const userTable = await accountService.execAsync(query) as undefined as IWireDataTable
```

Sometimes the format of the data returned from the data service call is unknown.  The `getResponseTable` method on the data source can be used to transform the response data into a data table.  Here, the data source will reach into the service provider for this transform as it knows the native format of the result set.

```typescript
...
    
const userData = await accountService.execAsync(query);

const userTable: IWireDataTable = accountService.getResponseTable(userData);
```

## Exec

The `exec` method is the synchronous equivalent of `execAsync`.  This method will pause the thread and wait for the results to come back from the data service call.

```javascript
...
const users = accountService.exec(query);
```

For details on these data source methods, visit the [DataSource](https://docs.wirebootstrap.com/wirebootstrap/reference/wire.data/wire.data.datasource) reference page.  For details on data tables, visit the [DataTable](https://docs.wirebootstrap.com/wirebootstrap/reference/wire.data/wire.data.datatable) reference page.