About | After Executing Sql statement Returns number of rows affected | Returns Single value, Executes first column first row only | Send the Command text to connection and builds a SqlDataReader. |
When we use | ExecuteNonQuery is used to perform Catalog operation like Creating table in database or Changing of data in tables (without using Dataset) by using Insert, Update, Delete, create | Selecting only single fields like count field | When we manipulating with DataReader it used, Sending SQL Select statements to a database, Invoking Stored Procedures |
Example | Example:
SqlCommand cmd = new SqlCommand("Insert Into SampleTable Values('1','2')",con);
//con is the connection object
con.Open();
cmd.ExecuteNonQuery(); //The SQL Insert Statement gets executed
This method returns no data at all. It is used majorly with Inserts and Updates of tables. It is used for execution of DML commands. | Example : select count(*) from emp
ExecuteScalar is used to get aggregate value. ExecuteScalar will return only one value that is first column value of the first row in the executed query.
Example 2:
cmd.CommandText = "Select Name, DOB, from Emp where ID=1";
Dim strName As string = cmd.ExecuteScalar.ToString
This returns one value only, no recordsets. | Example:
SqlConnection con = new SqlConnection(constr);
//constructor can be connection of string.
SqlCommand cmd = new SqlCommand ("select * from emp", con);
con.Open();
SqlDataReader dr = cmd. ExecuteReader (CommandBehavior. CloseConnection);
while(dr.Read())
{
Console.WriteLine (dr.GetString(0));
}
dr.Close();
//Implicitly closes the connection because CommandBehavior. CloseConnection was specified.
ExecuteReader is used to get set records by specified query |
No comments:
Post a Comment