What is the Traditional Network Library for a system?

In either Windows or POSIX systems, the named pipes provide ways of inter-process communications to connect different processes running on the same machine. It dispenses with the necessity of using the network stack, and data can be sent without affecting the performance. Servers set up named pipes to listen to requests. The client process needs to know the specific pipe name to send the request.

What are the different types of statements supported by SQL?

There are 3 types of SQL statements:

a) DDL (Data Definition Language): It is used to define the database structure such as tables. It includes three statements such as CREATE, ALTER, and DROP.

Also read =>> MySQL Create Table Tutorial

Some of the DDL Commands are listed below:

CREATE: It is used for creating the table.

CREATE TABLE table_name column_name1 data_type(size), column_name2 data_type(size), column_name3 data_type(size),

ALTER: The ALTER table is used for modifying the existing table object in the database.

ALTER TABLE table_name  ADD column_name datatype

OR

ALTER TABLE table_name DROP COLUMN column_name

b) DML (Data Manipulation Language): These statements are used to manipulate the data in records. Commonly used DML statements are INSERT, UPDATE, and DELETE.

The SELECT statement is used as a partial DML statement, used to select all or relevant records in the table.

c) DCL (Data Control Language): These statements are used to set privileges such as GRANT and REVOKE database access permission to the specific user.

Trapping Errors in Stored Procedures

A TRY CATCH block can catch errors in stored procedures called by other stored procedures.  An example is:

BEGIN TRY
    EXEC ParentError
END TRY
BEGIN CATCH
    SELECT Error_Line = ERROR_LINE(),
           Error_Proc = ERROR_PROCEDURE()
END CATCH

Assuming that the ParentError stored procedure calls the ChildError stored procedure which generates an error you'd see output like this:

Error_Line  Error_Proc
----------- -------------
5           ChildError

Handling SQL Server Errors

This article covers the basics of TRY CATCH error handling in T-SQL introduced in SQL Server 2005. It includes the usage of common functions to return information about the error and using the TRY CATCH block in stored procedures and transactions.

SQL Server uses the following syntax to capture errors in Transact-SQL statements:

BEGIN TRY
    SELECT [First] = 1
    SELECT [Second] = 1/0
    SELECT [Third] = 3
END TRY
BEGIN CATCH
    PRINT 'An error occurred'
END CATCH

This returns the following output:

First
-----------
1

(1 row(s) affected)

Second
-----------

(0 row(s) affected)

An error occurred

A key difference from SQL Server 2000 is that execution is halted when SQL Server encounters an error.  At that point execution transfers to the CATCH block.  This error isn't returned to the client application or calling program.  The TRY CATCH block consumes the error.