Flash MX 2004 Games : Art to ActionScript

Remember that a querystring takes the form
Chapter 14: Quizzes
varName1=varValue1&varName2=varValue2&varName3=varValue3&varName4=
varValue4&...
Each variable name and value are linked using the ampersand character. To turn the string into variable
data you can use the ‘Request’ command. The first section of the script turns the querystring
into the variables ‘category’, ‘difficulty’, ‘question’, and ‘A, B, C, D’.
An ASP page is cached by the browser so it is best to include the command
‘Response.Expires=0;’ at the beginning of the file to ensure that this caching does not take place,
otherwise the page can only be used once.
Having parsed the string into usable variables the ‘dbconnect.asp’ file is included in the file.
The effect of an include is as though the code in the file is actually part of this page. So if
everything has worked at this stage in the file you will have the variables to define a record in
the database and an open connection. Because the same ASP page is used for both updating
and adding we must first find out whether this question appears in the database. To do this
we will need another object, an ‘ADODB.recordset’, which is created in the same way as the
connection. Having created a recordset we use the ‘Open’ method passing a string and the open
connection. This time the string is an SQL query. To discover whether the record exists we
simply ask for a list of records containing this question using the SQL query ‘SELECT * FROM
quiz WHERE question=’ the current question. Here the table is ‘quiz’ and the only test is for
the single parameter ‘question’. The database engine then looks through all the records in the
‘quiz’ table for a match for the current question. Each time it finds a match it is added as a new
record to the object ‘rs’. We can move between records in the ‘rs’ object until we reach the end
when rs.EOF (End Of File) evaluates to true. If rs.EOF is false after the SQL query then the
question was not found. To allow us to use this information later in the code the variable ‘found’
is set to true or false based on the return value of the query: true if the question exists and false
if not.
Part of the information stored in the database is the date the record was added. To do this we
need to get the current date. Creating a variable using ‘new Date( )’ initializes the variable to a
‘Date’ object containing the current date. To use this with an SQL query we must convert the
format into a string. The string should be of the form
Month/Date/Year
where ‘Month’ is a number between 1 and 12, ‘Date’ is a number between 1 and 31 (depending
on the month) and the year is in the four-number format. The ‘Date’ object has methods for
returning this information, although the month is returned as a number between 0 and 11, so 1
must be added to achieve the SQL formatting.
We are nearly ready to update or add to the database. First we must format a query string
using the information we have discovered. If we are updating then we use the SQL command
‘UPDATE’. The format is to follow ‘UPDATE’ with the table name, and then use ‘SET’ and a
list of values to set separated by commas. So that SQL knows which record to update, the query
is completed by adding ‘WHERE’ with the column name ‘question’ being equal to the current
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