Common mistakes in Getting started with the asp.net2.0 database

The following list provides the most common errors that students find in an experimental installation, and if you have a problem, you can find out if there is a similar situation:

• Name or path of the incorrect MDB file--re-check the name and path of the exact MDB. To avoid errors in the path name, you can use the browse button in the AccessDataSource Configure Data Source Wizard.

• Access permissions for incorrect MDB files-if the MDB file requires UserID and passwords, you must use the techniques described in chapter 4th.

• Try to use a data-bound control when there is no data source control--the data-bound control must have a data source, or data source control, that is specified by the DataSourceID property.

• Set the wrong data source for the data-bound control-if you are using multiple data source controls, pay special attention to the exact name of each control. Then check the data source used in the DataSourceID property of each data-bound control again.

• Attempts to use mdb--while Jet is not yet installed on the machine check to see if the server has jet installed, although the number of times it occurs is small. It is easy to copy an MDB file, but you must also have a properly installed Access software or jet engine.

• Errors in table and column names-This error often occurs at the time of input, and if you use designer wizards or drag-and-drop methods in Visual Studio and VWD, there is no problem.

• Incorrect SQL statement syntax--Make sure you spell the keyword correctly. There must be a comma between each item in a list, such as a group of field names. The literal string must be within a pair of single quotes, but the number is not required. Whenever possible, create a statement by using the Configure Data Source dialog box for the DataSource control. You can also test SQL statements directly in the Access Query design tool or in Visual Studio QueryBuilder.

• Try to use a locked MDB object--an MDB table or query that is currently open in Access in design mode rejects all reads and writes. When you want to use the object in ASP.net, you need to close the object at design time or at run time.

• Attempts to modify a locked page--VWD Design view is not available for a page that is opened by a browser. If you need to use the Design view, you must first close the browser. (You can edit, save, and refresh the browser in the source view to view the changes).