Question

I have searched and found surprisingly few results. I found that there is some datatype property for DataColums, but when retrieving data from a SQL server database, what is the datatype of whatever is retrieved? I’m working with a SqlDataAdapter to fill a DataTable. To get the values, I work as follows:

DataTable dtt = Database.get(SQLString); //pseudo-code
string value = dtt.Rows[0][0]; //Or is this a string?

So what is in dtt.Rows[0][0] if the database column datatype is bigint, int, date or bit?
Do I need to convert them to string first and then convert them to other datatypes I require?

Answer 1

Well it depends how is defined in database, for example let’s say that you have this table :

CREATE TABLE [dbo].[Test](
    [ID] [int] NOT NULL,
    [Name] [nvarchar](128) NOT NULL,
    [Birthday] [datetime]) 

then you can access first row like that :

DataTable dtt = Database.get("Select * from Test"); //pseudo-code
DataRow rw = dtt.Rows[0];
int id = rw.Field<int>("ID");
string name = rw.Field<string>("Name");
DateTime dt = rw.Field<DateTime>("Birthday");

or

DataTable dtt = Database.get("Select * from Test"); //pseudo-code
int id = (int) dtt[0]["ID"];
string name = (string) dtt[0]["Name"];
DateTime dt = (DateTime) dtt[0]["Birthday")];