1. T-SQL and XML Enhancements in SQL Server 2005
1/3/2019 9:29 AM
T-SQL and XML Enhancements in SQL Server 2005
Eric Nelson
Application Architect
Microsoft
(SQL Dev and UK ISV)
NOTE: UPDATED SLIDES – this version will be made available for download in a few days.
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

2. Many TSQL enhancements…
Exception handling
TOP(expression)
PIVOT/UNPIVOT
APPLY
Common Table Expressions
Hierarchical queries
RANK
SNAPSHOT Isolation
VARCHAR(MAX), VARBINARY(MAX)…
XML Type
Full Text Search improvements
WAITFOR
Event Notifcations on DDL and DML
FOR XML
TABLESAMPLE
Service Broker
BULK INSERT …
Plus “none dev TSQL stuff”
Online Index Rebuild
Schemas
Certificates
Statement Level Recompile …

3. “If @@Error” programming sucks! There must be a better way…
Exception Handling
“If programming sucks! There must be a better way…

4. Exception Handling: TRY/CATCH
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Exception Handling: TRY/CATCH
Eliminate tedious “if code
Perform logging/cleanup when exceptions occur
Ability to re-raise exceptions after cleanup
BEGIN TRY
<core logic>
END TRY
BEGIN CATCH TRAN_ABORT
<exception handling logic>
END CATCH
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

5. Exception handling In CATCH block you can Transaction abort
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Exception handling
In CATCH block you can
Use new built-in functions to retrieve error-number, message, severity
Re-raise original exception or raise an alt
Transaction abort
Tx remains in “doomed” state until explicitly rolled back
No actions which result in log writes may be performed in a doomed transaction – SELECT only until you ROLLBACK
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

6. Transaction Abort Handling: Example
CREATE PROCEDURE nvarchar(1000) AS
int,
@error_severity int
BEGIN TRY
     BEGIN TRAN
          --Constraint violations cause txn/batch-abort;
          INSERT T1
     COMMIT TRAN
END TRY
BEGIN CATCH TRAN_ABORT
     ROLLBACK
     INSERT T1_Log GETDATE())
     SELECT @error_msg=error_message(), @error_num=error_number(), @error_severity=error_severity()
END CATCH
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

7. Drat …. I will not know until runtime how many rows I need…
TOP
Drat …. I will not know until runtime how many rows I need…

8. TOP (<expression>)
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TOP (<expression>)
SQL 7.0 and 2000
Provided TOP (n) with constant expression
Only for SELECT
SQL Server 2005
Provides TOP (<expression>)
Also available on INSERT/UPDATE/DELETE
int
-- at execution time
SELECT * FROM T
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

9. 1/3/2019 9:29 AM
TRY/CATCH TOP
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

10. PIVOT Columns, columns everywhere …. I need rows!
(And Access can already do it!)

11. PIVOT PIVOT UNPIVOT Transforms a set of rows to columns
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PIVOT
PIVOT
Transforms a set of rows to columns
Similar to Access TRANSFORM
Useful for data analysis
Useful for open shemas
E.g. Products with different properties
UNPIVOT
Reverse operation of PIVOT
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

12. Example: Simple PIVOT Make 1990 1991 Honda 2000 3000 Acura 500 600
Year
Sales
Honda
1990
2000
Acura
500
1991
3000
600
SELECT *
FROM SalesTable PIVOT(SUM(Sales) FOR Year IN ([1990], [1991])) s
Make
1990
1991
Honda
2000
3000
Acura
500
600
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

13. 1/3/2019 9:29 AM
PIVOT
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

14. Common Table Expressions
Temporary tables make some things so much easier to code– but that is so clunky… I need something better…

15. Common Table Expressions
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Common Table Expressions
As per SQL-99
Syntax:
WITH <CTEName> ( <column-list> ) AS
( <CTE>)
<SELECT using CTE>
Both recursive and non-recursive forms
Non-recursive:
Tidy code, avoid temp tables, views, sub selects
Recursive:
Rewrite queries with derived tables to be more readable
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

16. Example: CTE --Average number of times a Product was ordered
--for all Products that appeared on an order
--more than 50 times
WITH SalesCTE(ProductID, SalesOrderID) AS (
SELECT ProductID, COUNT(SalesOrderID)
FROM Sales.SalesOrderDetail
GROUP BY ProductID )
SELECT AVG(SalesOrderID)
FROM SalesCTE
WHERE SalesOrderID > 50

17. 1/3/2019 9:29 AM
Simple CTE
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

18. Recursive CTEs Recursive, when <CTE> references itself
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Recursive CTEs
Recursive, when <CTE> references itself
Recursive form of CTE
<non-recursive SELECT>
UNION ALL
<SELECT referencing CTE>
Recursion stops when 2nd SELECT produces empty results
Initialize
Accumulate
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

19. EXAMPLE: “Org Chart” No Recursive Queries
int
-- table variable to hold accumulated results
TABLE (empid nchar(5) primary key, empname nvarchar(50) NOT NULL, mgrid nchar(5), title nvarchar(30), processed tinyint default 0)
-- with direct reports of the given employee
SELECT empid, empname, mgrid, title, 0
FROM employees
WHERE empid = ‘12345’ =
-- While new employees were added in the previous iteration
> 0
BEGIN /*Mark all employee records whose direct reports are going to be found in this iteration with processed=1.*/
SET processed = 1
WHERE processed = 0
-- Insert employees who report to employees marked 1.
SELECT e.empid, e.empname, e.mgrid, e.title, 0
FROM employees r
WHERE e.mgrid=r.empid and e.mgrid <> e.empid and r.processed = 1
/*Mark all employee records whose direct reports have been found in this iteration.*/
SET processed = 2 WHERE processed = 1
END
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

20. EXAMPLE: “Org Chart” With Recursive Queries
WITH EmpCTE(empid, empname, mgrid) AS (
SELECT empid, empname, mgrid
FROM Employees
WHERE empid = ‘12345’
UNION ALL
SELECT E.empid, E.empname, E.mgrid
FROM Employees AS E JOIN EmpCTE AS M
ON E.mgrid = M.empid )
SELECT * FROM EmpCTE
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

21. I need to control how people change the schema of my database…how?
DDL Triggers
I need to control how people change the schema of my database…how?

22. DDL Triggers Extension of traditional triggers for DDL events
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DDL Triggers
Extension of traditional triggers for DDL events
Triggering events include all DDL statements
CREATE_TABLE, ALTER_PROCEDURE, DROP_LOGIN, etc.
Scoping at Database and Server levels
Event data available inside trigger through eventdata() function
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

23. EXAMPLE: DDL Triggers -- Log tables being dropped to dropLog
CREATE TABLE dropLog (id INT PRIMARY KEY IDENTITY, logTxt VARCHAR(MAX)) GO
-- Trigger to log drops
CREATE TRIGGER ddlDrop
ON DATABASE
AFTER DROP_TABLE AS
INSERT INTO dropLog
VALUES('A table has been dropped')

24. 1/3/2019 9:29 AM
DDL Triggers
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

25. DML with Output
It is a shame that I need to do two things to find out what rows I UPDATE or DELETE… is there a better way?

26. DML with OUTPUT OUTPUT clause for DML
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DML with OUTPUT
OUTPUT clause for DML
Ability to return rows as part of DML operations
Use “Inserted” and “Deleted” columns available to get pre- and post-update values
Option to store returned rows
OUTPUT… INTO…
TABLE (orderId int)
-- Update all 'unprocessed' to 'processed’
UPDATE Orders
SET status='processed'
OUTPUT INSERTED.orderId
WHERE status='unprocessed'
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

27. Ranking
I want to rank my data based on criteria … no, I don’t just mean order it…

28. Ranking Functions: Scenarios
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Ranking Functions: Scenarios
Data analysis (RANK, DENSE_RANK, NTILE)
Ability to generate ranks based on different criteria in same query
Ability to separate presentation order from ranks
Paging using ROW_NUMBER
Common scenario for walking through result sets
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

29. EXAMPLE SELECT RANK()OVER(ORDER BY City)
as RANK, RANK()OVER(PARTITION BY City ORDER BY LastName)
as PART_RANK, DENSE_RANK() OVER(ORDER BY City)
as DENSE_RANK, ROW_NUMBER() OVER(ORDER BY City)
as ROW_NUM, NTILE(4) OVER(ORDER BY City)
as NTILE_4, LastName, FirstName, City
FROM Employees
ORDER BY City, LastName
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

30. DML with Output RANK 1/3/2019 9:29 AM
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

31. SNAPSHOT Isolation
Hmmm …… I need more work to happen in parallel. How? OR
I am migrating from Oracle and want to do as few changes as possible

32. Snapshot Isolation SQL Server 2000 Transaction isolation levels
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Snapshot Isolation
SQL Server 2000 Transaction isolation levels
Read Uncommitted
Read Committed
Repeatable Read
Serializable
SQL Server 2005 adds...
Snapshot
Two flavours:
Statement = READ_COMMITTED
Transaction = SERIALIZABLE
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

33. Snapshot Isolation Increased data availability for read applications
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Snapshot Isolation
Increased data availability for read applications
Allows non-blocking consistent reads in an OLTP environment
Writers don’t block readers
Readers don’t block writers
Permits writes, which can cause conflicts
BUT…includes mandatory conflict detection
Snapshot Isolation trades:
cost of concurrency (locking exclusion) for
cost of CPU & I/O to construct transaction consistent view and read over versions
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

34. Snapshot Isolation: Scenarios
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Snapshot Isolation: Scenarios
Reporting and ad-hoc queries running concurrently with OLTP
Read-mostly database with relatively few writes
Applications prone to deadlocks may behave better
Consistent aggregates (e.g., AVG, SUM)
Migration from versioning databases
E.g. Oracle to SQL Server
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

35. I hate chunking data!!!! Please, tell me there is a better way…
Large data types
I hate chunking data!!!! Please, tell me there is a better way…

36. …(max) Type Text/nText and Image have problems
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…(max) Type
Text/nText and Image have problems
Most varchar functions don’t work (e.g. Like)
Not directly updateable
Not allowed as procedure variables
Extension to varchar, nvarchar, varbinary up to 2GB
CREATE TABLE myTable
(Id int,
Picture varbinary(max))
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

37. XML
I have rich XML outside the db – and strings inside the db . Is there a better way?

38. XML Support in SQL 2005 SQL Server 2005 as an XML store
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XML Support in SQL 2005
SQL Server 2005 as an XML store
Durable, recoverable, consistent
Mature management tools
Integration with existing relational data
SQL Server 2005 as an XML source
Accessible over HTTP and SOAP
Exposes all data as XML
Can be programmed just like a web service
Why XML? Sparse, unstructured, hierarchical or recursive data
Why store in SQL Server 2005? Transacted management, optimised queries, backup, interoperability, schema validation.
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

39. Native XML Store XML Data Type
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Native XML Store XML Data Type
XML data type
Native SQL type
Use for column, variable or parameter
CREATE TABLE docs (id INT PRIMARY KEY, xCol XML NOT NULL)
Well-formed and validation checks
Optional XML Schema enforcement
Behaviours allow XQuery and extensions
Exist, Query, Modify, Value
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

40. Native XML Store XML Index
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Native XML Store XML Index
Create XML index on XML column
CREATE PRIMARY XML INDEX idx_1 ON T (xCol)
CREATE XML INDEX idx_2 ON T(xCol)
USING XML INDEX idx_1 FOR PATH
Creates indexes on structure (PATH), properties (PROPERTY) values (VALUE)
Speeds up queries
Entire query is optimised
Same industry leading cost based optimiser
Indexes are used as available 56
Speeds up queries on the tags and values
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

41. 1/3/2019 9:29 AM
XML
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

42. Summary T-SQL is alive and kicking
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Summary
T-SQL is alive and kicking
There is LOTS more than covered today
Use T-SQL and CLR judiciously
Links:
Sample chapter
“A First Look at SQL Server 2005 for Developers”
Addison Wesley: Bob Beauchemin, Niels Berglund, Dan Sullivan
Books Online
- click on “Download Books Online” on right
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

43. © 2004 Microsoft Corporation. All rights reserved.
1/3/2019 9:29 AM
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.
© 2004 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

44. Code…