Querying Table Data Using Visual Basic Code in MS Access

In order to fully utilize the capabilities of MS Access, one must learn not only learn the Visual Basic (VB) programming language, but should also learn Standard Query Language (SQL). Once a grasp of these two languages have been obtained, MS Access users can begin to build faster and more efficient databases.

One tool that has proved itself very useful to me over the years is querying data from tables or queries using VB and SQL code. A brief introduction to this process is presented in this article. To best understand this process, an example is provided below along with an explanation of its parts.

'*********CODE***********

Dim rstTemp As Recordset

Dim strSQL As String

Dim routeNum As Integer

strSQL = "SELECT [Route], [Main Route PM], [Intersecting Route], [IntBeginPM], [IntEndPM] “

strSQL =  strSQL + “FROM Intersections_list WHERE (((CStr([Route])) = """ + cmbRouteQuery + """));"

Set rstTemp = CurrentDb.OpenRecordset(strSQL, dbOpenDynaset)

If (Not (rstTemp.EOF)) Then

rstTemp.MoveFirst

routeNum = rstTemp(0)

'************************


After the initial variable declarations, the code assigns an SQL statement to the string variable strSQL. This statement directs Access to gather all the data in the Route, Main Route PM, Intersecting Route, IntBeginPM, and IntEndPM fields of the table named Intersections_list. Furthermore, it directs Access to only gather information from these fields where the Route field is equal to a value held in the combo box cmbRouteQuery.

Once the SQL statement has been set, it is passed to the next line of code which executes it. It should be noted that the dbOpenDynaset variable is built into Access and holds an integer value that changes the type of recordset to open. For most general purposes, using dbOpenDynaset will work just fine.

The “if statement” in the code example verifies that the recordset just created contains information. If information is present, the code directs Access to move to the first record in the recordset. The code then stores the route in the first record (routeNum = rstTemp(0)) in the variable routeNum to be used for later use.

Nicholas Brown is a recognized authority on the subject of Access Databases. He is the founder of Database Technology Services (DTS). DTS is a leader in custom Access database development. DTS programmers create databases for corporations, small businesses and individuals. Visit www.dts-consultants.com to see all of the services DTS has to offer.

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