Student information management system 3

This blog was originally written after student information management 1 and 2. Later, something was delayed. Now, I will make up for it. Let's take a look at the difficulties and solutions we encountered in our student system.

 

1

This problem occurs frequently throughout the system.

The following error occurs: first, a problem occurs during data source connection;

Second, SQL statements have problems. This is mainly due to syntax errors, which must be known to everyone. I have a deep feeling. In the process of being missed, I realized that the SQL syntax is very strict. For example, if there are few spaces, the whole program cannot run. Sometimes I can't find an error, but I can't help it. I have to write the SQL statement again, so it's OK. We can see that its syntax is very important and strict.

 

There is a problem with data connection.

2. "The user already exists. Please enter the user name again !" Similar problems occur many times in the program.

 

1)

2)

 

Either case is a type error.

 

The cause of the error is that the if condition is replication rather than judgment (take a closer look at the if Statement () to find out the cause.

 

Error: when the statement cannot complete the judgment, but the program in the IF statement is always executed, it is probably because () is wrong, and the original judgment of the program is changed to a value assignment, in this way, if is always true, so it will always execute the if statement, and it is impossible to execute Else.

 

 

3. During the update operation, if the same item value of the same record is continuously modified

 

 

I did not really solve the problem, but I just used the method to avoid it. This method has many drawbacks and needs to be improved.

 

I did this:

1) avoid repeated occurrences,

For example, after modifying this record. after movenext modifies the information displayed on the form, the next message is automatically displayed. in this way, the values of the same field in the same record can be modified without repeated occurrences. (If there is only one, it is hard to say)

(2) If on
Error resume next, just jump over and execute the next statement, which is even more unreasonable.

 

 

 

These three problems are the most common problems encountered in my student system. They are also the problems that make me have a hard time solving. Therefore, I would like to share them with you.