Microsoft Access Database Programmer Tempe AZ

Microsoft Access Programmer Information

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The following material is shared here to indicate our commitment to professional Microsoft Access programmer services in the Tempe AZ area. Access programming for business is highly complex and requires dedication and skill to create a high quality database application. We wrote the book on Microsoft Access prgramming, so you know you will get the best possible Access database solution for your business.

Establishing Self-Joins

A self-join enables you to join a table to itself. This is often done so that information in a single table can appear to exist in two separate tables. A classic example is seen with employees and supervisors. Two fields are included in the Employees table: One field includes the EmployeeID of the employee being described in the record, and the other field specifies the EmployeeID of the employee's supervisor. If you want to see a list of employee names and the names of their supervisors, you'll need to use a self-join.

To build a self-join query, follow these steps:

1. Click the Query Design button in the Other group on the Create tab.

2. From the Show Tables dialog box, add the table to be used in the self-join to the query grid two times. Click Close. Notice that the second instance of the table appears with an underscore and the number 1.

3. To change the alias of the second table, right-click on top of the table in the query grid and select Properties. Change the Alias property as desired. In Figure 12.30, the alias has been changed to Supervisors.

4. To establish a join between the table and its alias, click and drag from the field in one table that corresponds to the field in the aliased table. In Figure 12.31, the SupervisorID field of the tblEmployees table has been joined with the EmployeeID field from the aliased table.

5. Drag the appropriate fields to the query grid. In Figure 12.31, the FirstName and LastName fields are included from the tblEmployees table. The SupervisorName expression (a concatenation of the supervisor's first and last names) is supplied from the copy of the table with the Supervisors alias.

TIP

You can permanently define self-relationships in the Relationships window. You will often do this so that you can establish referential integrity between two fields in the same table. In the example of employees and supervisors, you can establish a permanent relationship with referential integrity to make sure supervisor ID numbers aren't entered with employee ID numbers that don't exist.

Access Programmer for Tempe AZ Attribution

This material originally appeared in Alison Balter's book Mastering Microsoft Office Access 2007 Development. Reprinted here by author's permission.

When you need a Microsoft Access programmer for your Tempe AZ business, call MS Access Solutions at (323) 285-0939. We have over 25 years experience in Microsoft Access programmer solutions. We create Access database applications for all sectors, consisting of hospitals, government agencies, the U.S. military, universities, agriculture, workers services, and insurance provider. We can take care of the most advanced as well as complicated Access and SQL Server database programming for your business as well as smaller projects, like fixing damaged Access database forms, MS Access reports, Access macros, and VBA code.

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