How to avoid recording redundante data in database by MVC

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2.60/5 (2 votes)

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Hi,
I have a class with two properties (name,family).
I have wrote code for insert data into database without problem,but I dont know how to write code
for check the data is already exists or ?
anybody can guid me?

I needs sample for MVC 4 or higher.

Thanks in advanced

Posted 9-May-14 9:30am

sorosh04

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Vi(ky · Answer 1 · 2014-05-09T09:37:00

make "name" field unique. and before saving the new item

C#

public int AddProject(Project OProject)
       {
           var context = new DbSysEntities1();

           var original = (from p in context.Project
                          where p.ProjectName == OProject.ProjectName
                          select p).FirstOrDefault();
           if (original == null)
           {
              context.Project.Add(OProject);
              if (context.SaveChanges() > 0)
               return 0; //success
              else
               return 1; //error
           }
           else
           {
                return 2; //already exist
           }
       }

DamithSL · Answer 2 · 2014-05-09T09:33:00

Solution 1

you can create primary key for name or both name and family ( depending on your requirements)
When you have primary key, you can't insert duplicate values. You will get exception when inserting. using try.. catch[^] you can check the data already exist or not.

Posted 9-May-14 9:33am

DamithSL

Updated 9-May-14 9:35am

v2

Comments

sorosh04 9-May-14 15:35pm

How can I handle exceptions?
Its not better to select on table and compared with the textbox that user filled out and then decide its redundante data or not ?

DamithSL 9-May-14 15:41pm

then you need to call database twice in case of new record.