Validation of user entered data against Database

Question

How to check whether the value entered by the user in console exists in database? I have established a database connection. I got two values from console. I have to check whether the both value exists in database. http://ideone.com/8ALYrC(Source Code)

modeste modeste · Answer

hi thank you very much yesterday while i was sending the json code it only comes at one line but here in the attachment am sending a json file that i want to insert the description data into table in sql . i do not have any problem to send data into table using c# and sql . but the problem am having is to take description data in json as it is in the file and insert that content into a table of even displaying it into a text box. thank you very much

Bikesh Srivastava · Answer

use remote validation . see my article . http://www.c-sharpcorner.com/article/remote-validation-in-mvc-5-to-check-if-username-and-email-id-exists/

Ujjwal Gupta · Answer

you can execute the query - select count(*) from tablename where userid='your value'; function int IsDataExist(string value) { var query= selectcount(*)fromtablenamewheredata=' +value+ ' ; //tablename is the name of the table and data is the column name SqlCommand cmd= new SqlCommand(querycon); //conistheconnection con.open(); int result=cmd.executeScalar(); con.close(); return result; }

Afzaal Ahmad Zeeshan · Answer

You can use the SQL data reader object to iterate over the collection and see if the data exists or not. That would be simple as if (datafromDb==datafromUser){ //Dataexists. } Secondly you can even generate an SQL query that checks if the data exists or not for example if you have to check if a username afzaalahmadzeeshan exists or not you can do it like this varquery= SELECT*FROMtable_nameWHEREusername=@0 ; query.Parameters.Add( 0  afzaalahmadzeeshan ); //Orfromavariable This way once this executes it will return a record with this condition. If that condition meets it means there is a record otherwise none. This thread shares an in-depth overview of this scenario you can see that http://stackoverflow.com/questions/21302244/check-if-record-exists-in-database