ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with local SQL databases in AIR
Understanding statement parameters
Adobe AIR 1.0 and later
Frequently an application uses a single SQL statement multiple times in an application, with slight variation. For
example, consider an inventory-tracking application where a user can add new inventory items to the database. The
application code that adds an inventory item to the database executes a SQL INSERT statement that actually adds the
data to the database. However, each time the statement is executed there is a slight variation. Specifically, the actual
values that are inserted in the table are different because they are specific to the inventory item being added.
In cases where you have a SQL statement that’s used multiple times with different values in the statement, the best
approach is to use a SQL statement that includes parameters rather than literal values in the SQL text. A parameter is
a placeholder in the statement text that is replaced with an actual value each time the statement is executed. To use
parameters in a SQL statement, you create the SQLStatement instance as usual. For the actual SQL statement assigned
to the text property, use parameter placeholders rather than literal values. You then define the value for each
parameter by setting the value of an element in the SQLStatement instance’s parameters property. The parameters
property is an associative array, so you set a particular value using the following syntax:
statement.parameters[parameter_identifier] = value;
The parameter_identifier is a string if you’re using a named parameter, or an integer index if you’re using an unnamed
parameter.
Using named parameters
Adobe AIR 1.0 and later
A parameter can be a named parameter. A named parameter has a specific name that the database uses to match the
parameter value to its placeholder location in the statement text. A parameter name consists of the “:” or “@” character
followed by a name, as in the following examples:
:itemName
@firstName
The following code listing demonstrates the use of named parameters:
var sql:String =
"INSERT INTO inventoryItems (name, productCode)" +
"VALUES (:name, :productCode)";
var addItemStmt:SQLStatement = new SQLStatement();
addItemStmt.sqlConnection = conn;
addItemStmt.text = sql;
// set parameter values
addItemStmt.parameters[":name"] = "Item name";
addItemStmt.parameters[":productCode"] = "12345";
addItemStmt.execute();
Last updated 6/6/2012
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