Using Data - Page 4
November 27, 2000
Stuffing Data into a Variable
Sometimes we don't need the data to go directly to the page, in
which case we can save the information into a variable. For
example, we may need to perform some string manipulation or
validation prior to building the page.
VarNameFirst = ORSp("PeopleNameFirst")
The code on the above line stores the data into a variable for
later use. This must be performed within ASP delimiters, since
HTML lacks capacity to use variables.
The most common mistakes are:
- Attempting to perform this operation in HTML, outside of ASP
- Wrong RS name or wrong Field name
- Misspelled Field Name (very common error)
Using Data in an Expression
Data retrieved by ADO can be used directly in an expression. The
pseudo-code listings below show examples:
If ORSp("NameFirst")="Enrico" then
' code for Enrico
End If
In the above code we use the data in a field of the current
record of the oRSp recordset as the text to compare
against the word "Enrico." A similar test is performed in the
code below to determine if it is time to end the looping.
Do while NOT oRSp("NameFirst")="Enrico"
' code for people OTHER then Enrico
oRSp.MoveNext
Loop
If oRSp("Member") then
' code for members
Else
' code for non-members
End If
In our last case we switch to retrieving data from a different
field. The member field was established (at the time the database
was designed) as of type True/False. Therefore it will return a
value of true or false, which can be directly used as a whole
expression. If the database contains true the code for members
will be run.
The most common mistakes are:
- Attempting to perform this operation in HTML, outside of ASP
- Leaving the comparison sign (= or > or <) out of the
expression
- Writing expressions where the two sides of the comparison
sign are of two different data types. For example, "Joe" should
not be compared to "2".
- Wrong RS name or wrong Field name
- Misspelled Field Name (very common error)
- Errors in upper/lower case for data stores that are case
sensitive
- Quotes around numerical values
Using Data as an Argument in a Function
Data read by ASP-ADO can be used as an argument for another
function. For example:
VarNameFirstLetter = Left(oRSp("PeopleNameFirst"),1)
VarPassword = lCase(oRSp("PeopleNameFirst"))
VarSpaceLocation = instr (oRSp("PeopleNameFirst")," ")
Although the above works, many coding shops prefer that you first
read the data into a local variable. It is easier to read and
maintain code without all of the quotes and parentheses.
The most common mistakes are:
- Attempting to perform this operation in HTML, outside of ASP
- Providing data from ASP-ADO which is of the wrong type for
the argument
- Wrong RS name or wrong Field name
- Misspelled Field Name (very common error)
- Not writing test code to handle a request that returns a NULL
Syntax for Simple Recordsets - Page 3
Beginning ASP Databases
Using Recordset Data - Page 5
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