working-with-sql-statements.md

Working with SQL statements

An individual SQL statement (a query or command) is represented in the runtime as a SQLStatement object. Follow these steps to create and execute a SQL statement:

Create a SQLStatement instance.

The SQLStatement object represents the SQL statement in your application.

var selectData:SQLStatement = new SQLStatement();

Specify which database the query runs against.

To do this, set the SQLStatement object's sqlConnection property to the SQLConnection instance that's connected with the desired database.

// A SQLConnection named "conn" has been created previously
selectData.sqlConnection = conn;

Specify the actual SQL statement.

Create the statement text as a String and assign it to the SQLStatement instance's text property.

selectData.text = "SELECT col1, col2 FROM my_table WHERE col1 = :param1";

Define functions to handle the result of the execute operation (asynchronous execution mode only).

Use the addEventListener() method to register functions as listeners for the SQLStatement instance's result and error events.

// using listener methods and addEventListener()

selectData.addEventListener(SQLEvent.RESULT, resultHandler);
selectData.addEventListener(SQLErrorEvent.ERROR, errorHandler);

function resultHandler(event:SQLEvent):void
{
	// do something after the statement execution succeeds
}

function errorHandler(event:SQLErrorEvent):void
{
	// do something after the statement execution fails
}

Alternatively, you can specify listener methods using a Responder object. In that case you create the Responder instance and link the listener methods to it.

// using a Responder (flash.net.Responder)

var selectResponder = new Responder(onResult, onError);

function onResult(result:SQLResult):void
{
	// do something after the statement execution succeeds
}

function onError(error:SQLError):void
{
	// do something after the statement execution fails
}

If the statement text includes parameter definitions, assign values for those parameters.

To assign parameter values, use the SQLStatement instance's parameters associative array property.

selectData.parameters[":param1"] = 25;

Execute the SQL statement.

Call the SQLStatement instance's execute() method.

// using synchronous execution mode
// or listener methods in asynchronous execution mode
selectData.execute();

Additionally, if you're using a Responder instead of event listeners in asynchronous execution mode, pass the Responder instance to the execute() method.

// using a Responder in asynchronous execution mode
selectData.execute(-1, selectResponder);

For specific examples that demonstrate these steps, see the following topics:

Retrieving data from a database

Inserting data

Changing or deleting data