Table Warping by NULLS

Instead, many browsers will close up the empty space by shifting cells to the left to fill the gap. For example the cell that contains the Last Name gets shifted under the First Name heading, and all the rest of the row is similarly thrown off and a hole is generated all the way in the right column. Again, this is not a problem for all browsers, IE 4 and 5 heal this type of error well.

The shortest solution is to always concatenate an   before the data in your cells. This code will create a space before the data. Even if there is no data, the non-breaking space will hold the cell open. For example:

 Response.Write "<TD> " & oRSp("NameFirst") & "</TD>"

Although this trick solves the missing cell problem, it generates no small amount of angst in students. In the lines above we are using the ampersand for the same purpose, but in two different types of syntax. The first ampersand is for HTML, it is telling the browser to add in a non-breaking space after the <TD>. The second ampersand is for VBScript, telling it to add another term (the data in the NameFirst field) to its Response.Write string.

The first ampersand must go to the page so the browser can see it, therefore it must be within the double quotes. It will be printed on the page by ASP, and then go out to the network. The browser will interpret that into a non-breaking space and remove the   (also known as an entity name) from the user's view.

The second ampersand will be used by ASP to build the string <TD> John</TD> for Response.Write to put on the page. As that string is built, ASP removes the ampersand, it is never seen by HTML. That second ampersand must go outside the double quotes. The third ampersand is of the same type as the second.

This code can also be re-arranged to put the   after the data which will preserve left-aligned columns, as follows.

 Response.Write "<TD>" & oRSp("NameFirst") & " </TD>"

A less obtrusive technique is to insert the non-breaking space only if there is no data, as shown in the following code

If IsNull(oRSp("NameFirst")) Then
 Response.Write " "
Else
 Respone.write oRSp("NameFirst")
End If

A Note on Moving in Recordsets.

By default, when you open a simple recordset it is a forward only cursor. That means for walking through the records you have just two options:

MoveFirst
MoveNext

You can only go forward through the recordset. After you go through the recordset once you must use rs.MoveFirst prior to being able to go through the recordset again. There is frequently confusion from my students that you only get one pass through the recordset. But as long as after each pass you do a Move.First, you can pass through many times. But you can never back up through the records or jump ahead over records.

Summary

The most basic technique for reading data from a database can be accomplished in three lines, plus the lines to write the data to the page. The first line, Dim, sets aside a variable name, the second, SET, makes an instance of the recordset class, and the third uses the OPEN method to fill the object with a recordset.

Once filled, we can move down through the records of the recordset writing data to the page. Writing to the page is frequently done within an HTML table, which requires shifting back and forth between HTML tags and ASP-ADO data. When writing code you must be careful of a few traps including collapsed HTML cells from missing data.