Eliminating Roundtrips: TABLE Data Type and MERGE

www.cammanagementsolutions.com

19-Oct-2011

Presenters – Dinesh Priyankarahttp://dinesql.blogspot.com/

ELIMINATING ROUNDTRIPS:

TABLE DATA TYPE AND MERGE

http://dinesql.blogspot.com/


ROUNDTRIPS

Discussion


TABLE DATA TYPE

• SQL 2000– TABLE variable type

• SQL 2008– Ability to create user-defined TABLE data type

– Can be used for variables

– Can be used for parameters


TABLE DATA TYPE SUPPORTS

• Can use Row Constructor for inserting

• Can use with both INSERT and MERGE

• Multi-Row inserts is atomic

• Can use as a parameter for Stored Procedure– Cannot be used as an Output Parameter

– Must use READONLY with the definition


TABLE DATA TYPE

DEMO


MERGE STATEMENT

• Perform UPSERT operation– INSERT, UPDATE and DELETE

• Performs against Target using a source– Target: Table or View

– Source: Table, View, Derived Table, CTE, Table Function

• Atomic– Triggers will be fired only once


WHEN MATCHED THEN CLAUSE

• Allows to performs an action when the row is the source is found in the target

• Supported actions are: UPDATE and DELETE

• Supports two WHEN MATCHED clauses– One with AND predicate

– Second with or without AND predicate

– One must be UPDATE and other must be DELETE


WHEN NOT MATCHED BY TARGET AND BY SOURCE THEN CLAUSE

• BY TARGET – Default– Allows to performs an action when the row in the source is

NOT found in the target

– Only supported action is INSERT

• BY SOURCE– Allows to performs an action against rows in the target that

are not supplied with the source

– DELETE and UPDATE are supported


OUTPUT CLAUSE AND $ACTION

• OUTPUT Clause is available with MERGE

• $Action returns the operation performed

• Useful for logging/auditing


MERGE

DEMO


RESOURCES

• http://dinesql.blogspot.com/2012/01/table-type-and-merge-statement.html

http://dinesql.blogspot.com/2012/01/table-type-and-merge-statement.html




Q & A

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Eliminating Roundtrips: TABLE Data Type and MERGE

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