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Nuevas características del lenguaje T-SQL en SQL Server 2005

Nuevas características del lenguaje T-SQL en SQL Server 2005. Adolfo Wiernik adolfo@wiernik.net. Microsoft Regional Director - http://msdn.microsoft.com/isv/rd Mentor Solid Quality Learning - http://www.solidqualitylearning.com Fundador, Costa Rica User Group .NET - http://www.crug.net

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Nuevas características del lenguaje T-SQL en SQL Server 2005

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  1. Nuevas características del lenguaje T-SQL en SQL Server 2005

  2. Adolfo Wiernikadolfo@wiernik.net • Microsoft Regional Director - http://msdn.microsoft.com/isv/rd • Mentor Solid Quality Learning - http://www.solidqualitylearning.com • Fundador, Costa Rica User Group .NET - http://www.crug.net • Orador INETA Latinoamérica - http://www.ineta.org/latam • Blog - http://www.wiernik.net Jose Ricardo Ribeiroricardor@microsoft.com • En Microsoft desde 1998 • Desde el 2003 - Regional Program Manager • SQL Server Latinoamérica

  3. Series de Webcasts • Introducción a SQL Server 2005 para desarrolladoresViernes, 22 de Julio de 2005 06:00 p.m.(GMT)http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032277969&Culture=es-MX • Nuevas características del lenguaje T-SQL en SQL Server 2005Lunes, 25 de Julio de 2005 06:00 p.m.(GMT) http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032277973&Culture=es-MX • Aprovechando XML dentro de la base de datos con SQL Server 2005Viernes, 29 de Julio de 2005 06:00 p.m.(GMT) http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032277975&Culture=es-MX • Programando SQL Server 2005 con el CLR – Integración SQL-CLRLunes, 01 de Agosto de 2005 06:00 p.m.(GMT) http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032277977&Culture=es-MX • Nuevas características en ADO.NET 2.0Viernes, 05 de Agosto de 2005 06:00 p.m.(GMT)http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032277978&Culture=es-MX

  4. Nuevas Características para Desarrollo SQL Server Engine • SQL Service Broker • HTTP Support (Native HTTP) • Multiple Active Result Sets (MARS) • Snapshot Isolation Level Reporting Services • Multiple Output Formats • Parameters (Static, Dynamic, Hierarchical) • Bulk Delivery of Personalized Content • Support Multiple Data Sources • STS (Web Parts, Doc Libraries) • Visual Design Tool • Charting, Sorting, Filtering, Drill-Through • Scheduling, Caching • Complete Scripting Engine • Scale Out architecture • Open XML Report Definition Notification Services SQL Server Mobile Edition MDAC • SNAC • Microsoft Installer base setup ADO.NET 2.0 • Notification Support • Object Model enhancements SQL Client .NET Data Provider • Server Cursor Support • Asynchronous Execution • System.Transactions Security • Separation of Users and Schema • Data encryption primitives Administration • SQL Management Objects (SMO) • Analysis Management Objects (AMO) • Replication Management Objects (RMO) T-SQL • Recursive Queries • Common Table Expressions • PIVOT – UNPIVOT Operators • APPLY Operator • Exception Handling .NET Framework • Common Language Runtime Integration • User-defined Aggregates • User-defined Data Types • User-defined Functions • SQL Server .NET Data Provider • Extended Triggers Data Types • Managed SQL Types • New XML Datatype • Varchar (MAX) Varbinary (MAX) XML • XQUERY Support • XML Data Manipulation Language • FOR XML Enhancements • XML Schema (XSD) Support • MSXML 6.0 (Native) • .Net XML Framework Full-text Search • Indexing of XML Datatype

  5. Agenda • Exception Handling • Common Table Expressions (CTE) • PIVOT • Ranking and Partitioning • Cross-Outer Apply • TOP enhancements • Auto output • Large Objects (LOBs) • Synonyms • DDL Triggers

  6. Handling exceptions • SQL Server 2005 adds exception handling • Error handling in previous SQL Server versions was tedious • @@ERROR set on each statement • set variable with @@ERROR, then check value • BEGIN-END TRY BEGIN-END CATCH blocks in SQL 2005 • semantic equivalent of BEGIN-END blocks • additional functions return error info • can query transaction status • can save @@ERROR

  7. Error handling functions • New error information functions • available inside catch block • ERROR_NUMBER() - number of the error • ERROR_SEVERITY() - severity • ERROR_STATE() - error state number • ERROR_MESSAGE() - complete text of the error message • ERROR_LINE() – line number that caused the error • ERROR_PROCEDURE() – name of the routine that cause the error • New transaction information function • operation that forced logic into catch block may cause un-commitable transaction • XACT_STATE() – state of transaction • 1 = transaction is active and valid • -1 = transaction is uncommittable • 0 = there is no transaction

  8. Exception handling example -- catch errors in a procedure CREATE PROCEDURE someproc AS BEGIN BEGIN TRY SELECT * FROM authors END TRY BEGIN CATCH SELECT ERROR_NUMBER() END CATCH END GO -- catch errors in a batch BEGIN TRY SELECT * FROM authors END TRY BEGIN CATCH -- Test tx state IF (XACT_STATE()) = -1 ROLLBACK TRANSACTION IF (XACT_STATE()) = 1 COMMIT TRANSACTION END CATCH GO

  9. Common Table Expressions • CTE is a temporary named resultset • specified by starting query with a WITH keyword • can be replacement for subquery and used in view • can be used with SELECT/INSERT/UPDATE/DELETE WITH mid AS ( SELECT ((MAX(value) - MIN(value)) / 2) AS midval FROM invoices ) SELECT CASE WHEN value > mid.midval THEN 0 ELSE 1 END AS half, invoices.* FROM invoices, mid ORDER BY half calculates median value compares to median value categorize invoice by relative value

  10. Common Table Expression Syntax • Common table expression starts with WITH clause • expression in parentheses, preceded by name AS • Multiple common table expressions, comma separated • Followed by SELECT statement first cte, named low WITH low AS (SELECT ((MAX(amount)) / 3) AS v FROM invoices), high AS (SELECT (2 * MAX(amount) / 3) AS v FROM invoices) SELECT id, amount, amount - low.v FROM invoices, low, high WHERE invoices.amount > low.v AND invoices.amount <= high.v second cte, named high SELECT statement refers to high and low common table expression syntax

  11. Common table expression execution • CTE is evaluated only once • less scans than subquery if used more than once WITH low AS (SELECT ((max(amount)) / 3) AS v FROM invoices), high AS (SELECT (2 * max(amount) / 3) AS v FROM invoices) select id, amount, amount - low.v FROM invoices, low, high WHERE invoices.amount > low.v AND invoices.amount <= high.v evaluated once SELECT id, amount, amount - (SELECT (max(amount) / 3) FROM invoices) FROM invoices where amount > (SELECT (max(amount) / 3) FROM invoices) and amount < (SELECT (2 * max(amount) / 3) FROM invoices) evaluatedtwice SELECT middle third of invoices

  12. leaf value = 14 7 descendants 3 3 depth = 3 1 3 5 1 3 4 leaf 3 5 recursive calculations Recursive calculations • Hierarchy may be of inconsistent depth • chart of accounts and parts list are typical • Calculations require traversal of hierarchy • Many useful recursive calculations possible • aggregates, e.g. sum of leaves is rollup value of account • leaves, e.g. bill of materials for parts list

  13. Recursive common table expression • Common table expression can do recursive calculation • Recursive common table expression has three parts • anchor, followed by UNION ALL; does initialization • recursive member after UNION ALL; recurses until no results • outer select; selects results to be returned WITH descendant(parent, id, amount) AS (SELECT parent, id, amount FROM partsTree WHERE id = @start UNION ALL SELECT P.parent, P.id, P.amount FROM partsTree AS P INNER JOIN descendant AS A ON A.id = P.parent ) SELECT id FROM descendant anchor; executed once recursive member; repeated joined with previous recursion outer select; id's returned

  14. Recursive query example id parent 1 NULL 2 NULL 3 2 4 2 5 3 invoices table recursive common table expression WITH descendant(parent, id, amount) AS (SELECT parent, id, amount FROM partsTree WHERE id = 2 UNION ALL SELECT P.parent, P.id, P.amount FROM partsTree AS P INNER JOIN descendant AS A ON A.id = P.parent ) SELECT id FROM descendant select the cte 2, 3, 4, 5 results

  15. Unknown properties • Sometimes properties of products not known in advance • paint has color, type, and amount; bolt has pitch, diameter • Every property has a name and value • one to many solution; one table for products, one for properties • Individual product tables sometimes needed

  16. Pivot • Pivot turns columns into rows • in effect it synthesizes a table • Widens table by adding columns to it • pivot can rotate many table from one to many solution

  17. Basic pivot • Pivot needs three basic pieces of information • columns that makeup rotated table • column that contains value for rotated table columns • pivot column, i.e. the many in the one to many relation SELECT * FROM properties PIVOT ( MAX(value) FOR name IN ([color], [type], [amount]) ) AS P WHERE id IN (SELECT id FROM products WHERE name='Swish') value column pivot column make column where name = one of these select only properties for the Swish product

  18. Basic pivot results • Pivot selects all rows for a particular product • Columns not mentioned in pivot used to group properties id not mentioned in pivot expression id color type amount -- ------- -------- ------- 1 blue oil 1 gal 3 red latex 1 qt 4 white oil 1 pt properties grouped by id pivoted properties of Swish product

  19. Pivot and Unpivot • The PIVOT keyword makes • rows into columns and aggregates values • generates crosstab reports • UNPIVOT does the opposite • rotates columns to rows (not always symmetric w/PIVOT) -- quantity by quarter CREATE TABLE quarterlysales( product varchar(50), quarter int, quantity int) GO SELECT product, [1] AS 'Q1', [2] AS 'Q2', [3] AS 'Q3', [4] AS 'Q4' FROM quarterlysales PIVOT(SUM(quantity) FOR quarter IN ([1], [2], [3], [4])) AS P

  20. Ranking and Windowing Functions • Adds a column to resultset based on ratings • ROW_NUMBER • RANK • DENSE_RANK • NTILE(n)

  21. Ordering • Column to be rated specified in ORDER BY clause • there must be at least one ordering column • can be more than one SELECT orderid, customerid, ROW_NUMBER() OVER(ORDER BY orderid) AS num FROM orders WHERE orderid < 10400 AND customerid <= 'BN'

  22. Ranking Functions and Ties • Ties work differently in different functions • ROW_NUMBER – always unique • RANK – ties produce spaces and dups in ranking • DENSE_RANK – dups but not ties • NTILE(n) – divided into n approximately equal parts

  23. Duplicates and ties SELECT orderid, customerid, ROW_NUMBER() OVER(ORDER BY customerid) AS num, RANK() OVER(ORDER BY customerid) AS [rank], DENSE_RANK() OVER(ORDER BY customerid) AS [denserank], NTILE(5) OVER(ORDER BY customerid) AS ntile5 FROM orders WHERE orderid < 10400 AND customerid <= 'BN' orderid customerid num rank denserank tile5 ----------- ---------- ------ ------ --------- ------ 10308 ANATR 1 1 1 1 10365 ANTON 2 2 2 1 10355 AROUT 3 3 3 2 10383 AROUT 4 3 3 2 10278 BERGS 5 5 4 3 10280 BERGS 6 5 4 3 10384 BERGS 7 5 4 4 10265 BLONP 8 8 5 4 10297 BLONP 9 8 5 5 10360 BLONP 10 8 5 5

  24. Windowing • You can divide the resultset into subgroups • known as windows • use "PARITITION BY" in the OVER clause • each partition has its own ranking

  25. Windowing SELECT *, RANK() OVER(PARTITION BY COUNTRY ORDER BY age) AS [rank] from ( SELECT lastname, country, DATEDIFF(yy,birthdate,getdate()) as age FROM employees ) AS a lastname country age rank -------------------- --------------- ----------- ------ Dodsworth UK 37 1 Suyama UK 40 2 King UK 43 3 Buchanan UK 48 4 Leverling USA 40 1 Callahan USA 45 2 Fuller USA 51 3 Davolio USA 55 4 Peacock USA 66 5

  26. OVER and other aggregates • OVER can be used with other aggregates • includes user-defined aggregates • usually produces groups of duplicate values

  27. Over with max aggregate -- there is one oldest employee age for each country select *, RANK() OVER(PARTITION BY COUNTRY ORDER BY age) as [rank], MAX(age) OVER(PARTITION BY COUNTRY) as [oldest age in country] from ( select lastname, country, datediff(yy,birthdate,getdate()) as age from employees ) as a lastname country age rank oldest age in country -------------------- --------------- ----------- ------ ---------- Dodsworth UK 37 1 48 Suyama UK 40 2 48 King UK 43 3 48 Buchanan UK 48 4 48 Leverling USA 40 1 66 Callahan USA 45 2 66 Fuller USA 51 3 66 Davolio USA 55 4 66 Peacock USA 66 5 66

  28. Apply operators • APPLY is join • no ON clause allowed • Right part can be any table, but meant for table UDF • params for UDF can come from columns of left part • Cross and outer apply available amount comes from invoice row SELECT * FROM invoice CROSS APPLY greater(amount, 1500) each invoice row joined to table returned by greater function must return table SELECT I1.*, I2.amount FROM invoice I1 JOIN invoice I2 ON I2.amount > 1500 AND I2.id = I1.id equivalent join

  29. Cross apply • Cross apply does inner join • no output for row when UDF produces no output • udf can get its parameters from LHS • useful when udf uses column from LHS CREATE FUNCTION Greater(@v float, @t float) RETURNS TABLE AS RETURN SELECT @v AS v WHERE @v > @t returns either nothing or table with single row returns rows from invoicewhere value > 1500 SELECT * FROM invoice CROSS APPLY Greater(invoice.amount, 1500) @v value frominvoice table cross apply as filter constant passed in for @t

  30. Outer apply • OUTER APPLY does left outer join • all rows from left part returned • may have NULLs for columns returned by UDF CREATE FUNCTION greater(@v float, @t float) RETURNS TABLE AS RETURN SELECT @v AS v WHEN @v > @t returns all rows in invoice SELECT * from invoice OUTER APPLY greater(invoice.amount, 1500)

  31. TOP query • TOP query gets "first N" rows quickly • first page of grid • TOP query can now be based on expression • update TOP N rows aids in batching updating DECLARE @a int, @b int -- set @a and @b -- then, use expression SELECT TOP (@a/@b)* FROM license GO UPDATE TOP (3) license SET status = 'E' WHERE expire_date = getdate() GO

  32. OUTPUT clause on action statements • SQL action statements return "number of rows affected" • sometimes you want to know more • which rows were changed • you could change from a static cursor to get this info • what identity columns were generated • you could get @@ identity • both cases require extra work to return info to caller • OUTPUT clause on actions generate output • returned through TABLE variables • no addition program logic needed • can use logical tables to return before/after images

  33. Returning automatic output -- output rows of "before" values DECLARE @tab TABLE (c1 ....) UPDATE orders SET shipregion = 'RJ' OUTPUT c.*, INSERTED.* into @tab FROM orders o JOIN customers c ON o.customerid=c.customerid GO -- return default value and GUID CREATE TABLE T ( id int, name varchar(20), a TIMESTAMP, b UNIQUEIDENTIFIER) GO INSERT T OUTPUT INSERTED.* into @tab -- table variable VALUES (1, 'bob', DEFAULT, NEWID()) GO

  34. DDL Triggers • Events include all DDL statements • CREATE_TABLE, ALTER_PROCEDURE, DROP_LOGIN, etc. • Scoping at Database and Server levels • DDL_DATABASE_LEVEL_EVENTS • Eventdata() • Returns data regarding type of DDL event of type xml.

  35. Summary • T-SQL enhancements • exception handling added to T-SQL • most enhancements follow SQL-99 standard • CTE, hierarchical CTE • PIVOT, ranking and partitioning (part 8 - OLAP) • some enhance SQL Server specific functions • CROSS, OUTER APPLY • TOP • automatic output • DDL Triggers

  36. Recursos • SQL Server 2005 – Laboratorios Virtualeshttp://msdn.demoservers.com/login.aspx?group=sql2005http://www.microsoft.com/technet/traincert/virtuallab/sql.mspx(only supports SQL 2000) • SQL Server 2005 http://www.microsoft.com/sql/2005 • SQL Server Express http://www.microsoft.com/sql/express • Visual Studio 2005 http://lab.msdn.microsoft.com/vs2005

  37. Series de Webcasts • Introducción a SQL Server 2005 para desarrolladoresViernes, 22 de Julio de 2005 06:00 p.m.(GMT)http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032277969&Culture=es-MX • Nuevas características del lenguaje T-SQL en SQL Server 2005Lunes, 25 de Julio de 2005 06:00 p.m.(GMT) http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032277973&Culture=es-MX • Aprovechando XML dentro de la base de datos con SQL Server 2005Viernes, 29 de Julio de 2005 06:00 p.m.(GMT) http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032277975&Culture=es-MX • Programando SQL Server 2005 con el CLR – Integración SQL-CLRLunes, 01 de Agosto de 2005 06:00 p.m.(GMT) http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032277977&Culture=es-MX • Nuevas características en ADO.NET 2.0Viernes, 05 de Agosto de 2005 06:00 p.m.(GMT)http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032277978&Culture=es-MX

  38. Gracias adolfo@wiernik.net adolfo@solidqualitylearning.com

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