Question

I know I can read data from database using these three terms but can Any one please guide me properly when to use ExecuteScalar, ExecuteReader and DataSet??

Answer 1

When to use ExecuteScalar

ExecuteScalar: use it to execute any user defined function or the stored procedures, that usually has a scalar return value. i.e returns only one value. However, it can also be used with other queries or stored procedures, but in this case it returns only the first column of the first row in the result set returned by the query. Additional columns or rows are ignored.

When to use ExecuteReader

ExecuteReader: use it for the usual queries that you pose to the database or with the stored procedure. The CommendText property is what determines whether it is a query or a stored procedure name. It sends the CommandText to the Connection and builds a SqlDataReader that returns a set.

Data set is a different thing than the ExecuteReader and ExecuteScalar it represents an in-memory cache of data that are usually coming from the database.