Adobe 38040334 User Guide - Page 660

DREAMWEAVER CS3 653 User Guide Dreamweaver inserts ASP code in your page that, when run on the server, creates a command that inserts, updates, or deletes records in the database. By default, the code sets the Prepared property of the Command object to true, which makes the application server reuse a single compiled version of the object every time the command is run. To change this setting, switch to Code view and change the Prepared property to false. 7 Create a page with an HTML form so users can enter record data. In the HTML form, include three text fields (txtCity, txtAddress, and txtPhone) and a submit button. The form uses the GET method and submits the text field values to the page that contains your command. About JSP prepared statements A JSP prepared statement is a reusable server object that contains a SQL statement. You can place any valid SQL statement in a prepared statement. For example, a prepared statement can contain a SQL statement that returns a recordset, or one that inserts, updates, or deletes records in a database. A prepared statement is reusable in the sense that the application server uses a single instance of the prepared statement object to query the database a number of times. Unlike the JSP statement object, a new instance of the prepared statement object is not created for each new database query. If you know the statement will be executed more than a few times, having a single instance of the object can make database operations more efficient and take up less server memory. A prepared statement object is created by a Java scriptlet on a JSP page. However, Dreamweaver lets you create prepared statements without writing a single line of Java code. If you're interested in the code, the following scriptlet creates a prepared statement: String myquery = "SELECT * FROM EMPLOYEES WHERE DEPARTMENT = ?"; PreparedStatement mystatement = connection.prepareStatement(myquery); The first line stores the SQL statement in a string variable called myquery, with a question mark serving as a placeholder for the SQL variable value. The second line creates a prepared statement object called mystatement. Next, you assign a value to the SQL variable, as follows: mystatement.setString(1, request.getParameter("myURLparam")); The setString method assigns the value to the variable and takes two arguments. The first argument specifies the affected variable by its position (here, the first position in the SQL statement). The second argument specifies the variable's value. In this example, the value is provided by a URL parameter passed to the page. Note: You must use different methods to assign non-string values to SQL variables. For example, to assign an integer to the variable, you would use the mystatement.setInt() method. Finally, you generate the recordset, as follows: ResultSet myresults = mystatement.execute(); Use JSP prepared statements to modify a database You can use Dreamweaver to create JSP prepared statements that insert, update, or delete records in a database. A JSP prepared statement is a reusable server object that contains a SQL statement. You supply the prepared statement with the SQL that performs the operation on the database. 1 In Dreamweaver, open the JSP page that will run the command. September 4, 2007