How to Check if Exist before I Save in ASP.NET MVC

mike idowu

I have this code, as shown below:

Please how do I check from the database if COUNTRY_CODE or COUNTRY_NAME exists in the database before I Save in the database

5 Replies

Know the answer? Post it — somebody with the same question will find it here.

Ramesh Palanivel8y ago
Accepted answer
Hi Mike,

You country Id always will be the same Id, While edit and update. Its PK and there is no chance to change it. So using your Id you can update,try the below code.
public void EditCountry(CountriesViewModel.CountriesInput countryModel)
{
    try
    {
        COUNTRIES newCountry = new COUNTRIES()
        {
            COUNTRY_ID = countryModel.COUNTRY_ID,
            COUNTRY_CODE = countryModel.COUNTRY_CODE.Trim(),
            COUNTRY_NAME = countryModel.COUNTRY_NAME.Trim(),
            ACTION_STATUS = 0,
            LAST_UPDATE_BY = int.Parse(System.Web.HttpContext.Current.User.Identity.GetUserId().ToString()),
            LAST_UPDATE_DATE = DateTime.UtcNow
        };
        if (backendDB.COUNTRIES.Where(x => x.COUNTRY_CODE == newCountry.COUNTRY_CODE && x.COUNTRY_NAME == newCountry.COUNTRY_NAME && x.Country_Id != newCountry.Country_ID).Any())
        {
            //Return error Message
        }
        else
        {
            backendDB.COUNTRIES.Add(newCountry);
            backendDB.Entry(newCountry).State = EntityState.Modified;
            backendDB.SaveChanges();
        }

    }
    catch (Exception ex)
    {
        // Info
        throw ex;
    }
}
0
mike idowu8y ago
Ramesh Palanivel has solved the problem. But how do I apply it to Edit/Update as shown below.

0
Ramesh Palanivel8y ago
Hi Mike,

Try the below code,
public void AddCountry(CountriesViewModel.CountriesInput countryModel)
{
    COUNTRIES newCountry = new COUNTRIES()
    {
        COUNTRY_ID = countryModel.COUNTRY_ID,
        COUNTRY_CODE = countryModel.COUNTRY_CODE.Trim(),
        COUNTRY_NAME = countryModel.COUNTRY_NAME.Trim(),
        ACTION_STATUS = 0,
        CREATED_BY = int.Parse(System.Web.HttpContext.Current.User.Identity.GetUserId().ToString()),
        CREATED_DATE = DateTime.UtcNow,
    };
    if (backendDB.COUNTRIES.Where(x => x.COUNTRY_CODE == newCountry.COUNTRY_CODE && x.COUNTRY_NAME == newCountry.COUNTRY_NAME).Any())
    {
        //Return error Message
    }
    else
    {
        backendDB.COUNTRIES.Add(newCountry);
        backendDB.SaveChanges();
    }

}
0
Laxmidhar Sahoo8y ago
sir first cretate the object like you have .

COUNTRY newCountry = new COUNTRY();
newCountry.COUNTRY_CODE = countryModel.COUNTRY_CODE.trim().

If COUNTRY_CODE is exit then entity will cretae if automaticaly
0
Shweta Lodha8y ago
Before inserting the data, you can verify if schema is matching or not.

You can verify this by calling call CompatibleWithModel(). This method will tell you if the DB matches the model or not. If parameter is set to true it will throw an exception if no model data is present in the DB.

bool isSchemaValid = context.Database.CompatibleWithModel(true);

I think. in your case context is backendDB. Based on this you can take decision.
+1