primary key error in asp.net web page

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I am working on a webbased application(Employee registration form). In which I am storing user information in SQL server. I have text box to insert the employ id no., on textbox textchange event (it will verify the id is valid or not,from another table where only employ idno.s are stored), If it is a valid id no. then it will allow to enter other details like(Ename, address, contact no:,...etc). On clicking submit button all this information will be saved in database table called EmpRegister. In EmpRegister table I have primary key on EID column, if an employee try to register for more than one time, it is giving server error.
Can anybody help me regarding this, On text change event two things should happen (1. It should check it is a valid id or not fro EIDS table of database, 2. If that id is already registered in EmpRegister table,then it should not give server error, Instead we can give an error message that "Already Registered").
Kindly help me with the code, I am new to programming. Thanks in advance.

Posted 23-Jan-13 5:22am

2012programmer

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Pallavi Waikar · Answer 1 · 2013-01-23T05:37:00

do your validations...before inserting check ....is employee is registered or not..exampal

C#

cmd=("Select count(*) from employee where emp_name='"+txtEmpName.Text+"'",con);
Int32 hh=convert.ToInt32(cmd.ExecuteScaler());

if(hh==0)
{
//your insert coading
}
else
{
//give alert message employee already registered
}

change select as per your requirement i.e in where check EID or empname...

techgeek from-india · Answer 2 · 2013-01-23T05:43:00

Solution 2

Just define EID as a primary key field and while inserting a data it will check an unique and not null data from table.
and if user is already existing with a same EID it will throw an error.

Posted 23-Jan-13 5:43am

techgeek from-india

__TR__ · Answer 3 · 2013-01-23T06:18:00

Solution 3

I am not sure why you would need another table to store Employee Id numbers. You can include everything in one table and you can use IDENTITY (Property)[^] to auto generate the EId column. Here is a sample of how your table would look.

SQL

CREATE TABLE EmpRegister
(
   EId INT IDENTITY(1,1) CONSTRAINT PK_EmpRegister PRIMARY KEY, --This is the primary key that is auto generated
   EmployeeId VARCHAR(100), --This is the employee ID entered by user.
   EName VARCHAR(100),
   Address VARCHAR(100),...
)

When User enters the Employee Id you can check if it exists or not like this
SELECT COUNT(*) FROM EmpRegister WHERE EmployeeId = 'Value entered by user'
If the EmployeeId entered by user already exists the count will return a non zero value else it will return 0.

Posted 23-Jan-13 6:18am

__TR__

Comments

2012programmer 23-Jan-13 15:19pm

First of all I thank you for your help.
For example, there is 1500 employees. These employee id's are stored in a table(EIDS), But My requirement is to register only 50 employes(EmpRegister table) from those 1500 employees. I need two types of validations, 1. The user entered id must be present in EIDS table, 2. EmpRegister table should not include duplicate records(For this purpose "EID" column of EmpRegister table has a primary key- this is working fine, but if there is duplicate value try to insert into database table- it is giving Server Error in the browser, this is not looking good in the browser, what I need is just give an alert message that "Already Registered".

__TR__ 24-Jan-13 1:37am

I am having difficulty understanding your requirement.
What is the criteria for registering only 50 employees out 1500 employees?

What if an employee enters an Id that is present in EIDS table but the Id was assigned to someother employee. How do you plan to handle such a scenario ?

What exactly is it that you are trying to do here ?

2012programmer 24-Jan-13 15:32pm

I am planning a training program for employees, for that employees will register on a asp.net web page. If there 1500(for example), but the training program is designed for 50 employs only.
My requirement: Somebody can fill my database with garbage values. To avoid this, I have EIDS table in which all employ ids are stored, If a user try to enter gargabe value, then it will check with EIDS table then it will allow you to enter other details. This is working fine. But another requirement if an employ try to re-register it is giving "Server Error", Instead of server error can we provide an alert box with "already registered"

__TR__ 25-Jan-13 2:13am

That should be easy. Just find out if the user has already registered before doing an insert. If the record is already inserted don't do anything in database and show a message to user saying s/he has already registered, else insert the record. Let me know if you have any questions. Also it would be helpful if you show the table structures when ask your question.

2012programmer 26-Jan-13 2:35am

I am inserting the record when a user click on button. But Iam checking the userid is correct or not in text change event. In text change event only can I check the user is already registered or not.

__TR__ 28-Jan-13 10:50am

In that case just pass the user id entered in the textbox to database and check if it exists in the table.