In my winform application I have the following scenario:
I want to get multiple tables on a single event. Returning all tables as dataset
in single server cycle,
or getting one table at time and using separate server cycle for each table
which one is better? What are the advantages one over another?
Most stored procedures return multiple result sets. Such a stored procedure usually includes one or more select statements. The consumer needs to consider this inclusion to handle all the result sets.
The RETURN exits the stored procedure, and nothing that follows it will be executed, including the SELECT statement on the following line. Otherwise, if you want the data for the entire table, as your question shows, add a SELECT after the INSERT . But don't put RETURN in front of it!
In order to fetch the multiple returned values from the Stored Procedure, you need to make use of a variable with data type and size same as the Output parameter and pass it as Output parameter using OUTPUT keyword. You can also make use of the Split function to split the comma separated (delimited) values into rows.
You can't return multiple values from stored procedure in the way you are doing it now. You can, however, specify your parameters to be OUTPUT so you can access them. See here[^] for additional explanation.
The normal way is to get all at once.
just construct your SELECT
's and you will have a DataSet
filled with all tables.
using (System.Data.SqlClient.SqlConnection conn = new System.Data.SqlClient.SqlConnection(myConnString)) { using (System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand()) { cmd.CommandText = "myMultipleTablesSP"; cmd.Connection = conn; cmd.CommandType = CommandType.StoredProcedure; conn.Open(); System.Data.SqlClient.SqlDataAdapter adapter = new System.Data.SqlClient.SqlDataAdapter(cmd); DataSet ds = new DataSet(); adapter.Fill(ds); conn.Close(); } }
if for example you return 2 tables in your SP, like:
SELECT * FROM [TableA]; SELECT * FROM [TableB];
you would access this tables as:
DataTable tableA = ds.Tables[0]; DataTable tableB = ds.Tables[1];
If you load each table separately and use threads you can greatly improve the performance.
Datasets are also very heavy weight... so try avoiding them if possible.
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