Tsql Exception Handling

TSQL Exception Handling

By Rajib Bahar

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Agenda • • • • • • • • •

What is exception handling? Simple C# exception mechanism The way we used to handle it… How is it done in TSQL? Demo What are ways to handle at client end? Demo Reflection Additional Information 2

What is exception handling? • Exception Handling is simply a breach of an application's predefined assumptions. It enables us to provide a reliable data/process validation mechanism in our applications. • SQL Server did not have any close counterpart for it until now.

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Simple C# exception mechanism

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The way we used to handle it… • @@ERROR – would give us the status result of last statement. If it wasn’t 0 then we know some deviant behavior occurred. • RaiseError method. • Outside of scope to discuss above two in detail

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How is it done in TSQL? BEGIN TRY      { sql_statement | statement_block } END TRY BEGIN CATCH      { sql_statement | statement_block } END CATCH [ ; ]

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Demo

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What are ways to handle at client end?

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Demo

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Reflection As you may have noticed… • There is no concept of finally clause. • No standard mechanism for rethrowing exceptions. • No throwing (i.e. throw new Exception(…))

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Additional Information • Resources – SQL Server Books Online • BEGIN CATCH statement

– Code Project

• http://www.codeproject.com/database/ExceptionHandli - Try and Catch Fun SQL Server

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Questions? •?

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Thank You! Rajib Bahar

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