Module 9: Using Advanced Techniques

Considerations for Querying Data Working with Data Types Cursors and Set-Based Queries Dynamic SQL Maintaining Query Files

Lesson 1: Considerations for Querying Data Execution Plans Data Type Conversions Implicit Conversions Explicit Conversions with CAST and CONVERT Data Type Precedence

Execution Plans Shows how the Database Engine navigates tables and indexes View Estimated Execution Plan before query execution View Actual Execution Plan after execution Generate Execution Plans with: SQL Server Management Studio T-SQL SET options SQL Server Profiler

Demonstration: Using Execution Plans In this demonstration, you will learn how to: View estimated and actual execution plans

Data Type Conversions Data Type Conversion scenarios Data is moved to, compared, or combined with other data Data is moved from a result column, return code, or output parameter into a program variable Implicit Conversion Transparent to the user Explicit Conversion Uses CAST or CONVERT

Implicit Conversions char(10) = 'Kevin' SELECT FirstName, LastName FROM Person.Person = FirstName char(10) = 'Kevin' SELECT FirstName, LastName FROM Person.Person = FirstName

Explicit Conversions with CAST and CONVERT Using CAST USE AdventureWorks2008; GO SELECT SUBSTRING(Name, 1, 30) AS ProductName, ListPrice FROM Production.Product WHERE CAST(ListPrice AS int) LIKE '3%'; GO Using CONVERT USE AdventureWorks2008; GO SELECT SUBSTRING(Name, 1, 30) AS ProductName, ListPrice FROM Production.Product WHERE CONVERT(int, ListPrice) LIKE '3%'; GO

Data Type Precedence Without explicit conversion, this statement fails int Number ' = 1 With explicit conversion, this statement succeeds int Number ' = 1 +

Demonstration: Understanding Data Type Conversion In this demonstration, you will learn how to: Understand explicit and implicit data type conversions Use CAST and CONVERT to explicitly convert data types

Lesson 2: Working with Data Types Recommendations for Querying Date/Time Data Recommendations for Inserting Date/Time Data Implementing the hierarchyid Data Type Working with Hierarchies

Date/Time values can be queried using numeric operators such as =, >, and < as well as date/time functions. When querying date/time data, care must be taken in understanding the data type. Recommendations for Querying Date/Time Data DATETIME, DATETIME2, & DATETIMEOFFSET data types Query conditions must include both date and time portions. DATE data type Query conditions must include just the date portion. TIME data type Query conditions must include just the time portion.

Recommendations for Inserting Date/Time Data SET DATEFORMAT mdy GO datetime = '12/31/2008' SET DATEFORMAT mdy GO datetime = '12/31/2008' SET DATEFORMAT ydm GO datetime = ‘2008/31/12' SET DATEFORMAT ydm GO datetime = ‘2008/31/12' SET DATEFORMAT ymd GO datetime = ‘2008/12/31' SET DATEFORMAT ymd GO datetime = ‘2008/12/31' Use correct format and language settings Use language independent formats for portability

Demonstration: Working with Date/Time Data In this demonstration, you will learn how to: Use the correct methods for working with various date/time data types

Implementing the hierarchyid Data Type CREATE TABLE Organization ( EmployeeID hierarchyid, OrgLevel as EmployeeID.GetLevel(), EmployeeName nvarchar(50) NOT NULL ) ; GO CREATE TABLE Organization ( EmployeeID hierarchyid, OrgLevel as EmployeeID.GetLevel(), EmployeeName nvarchar(50) NOT NULL ) ; GO

Working with Hierarchies CREATE CLUSTERED INDEX Org_Breadth_First ON Organization(OrgLevel, EmployeeID); GO CREATE CLUSTERED INDEX Org_Breadth_First ON Organization(OrgLevel, EmployeeID); GO CREATE UNIQUE INDEX Org_Depth_First ON Organization(EmployeeID); GO CREATE UNIQUE INDEX Org_Depth_First ON Organization(EmployeeID); GO

Demonstration: Using the hierachyid Data Type In this demonstration you will learn how to: Work with the hierarchyid data type

Lesson 3: Cursors and Set-Based Queries Understanding Cursors Cursor Implementations Using Cursors Understanding Set-Based Logic

Cursors extend processing of result sets Understanding Cursors Allow positioning at specific rows Retrieve one or more rows from the current position Support data modification Support different levels of visibility Provide T-SQL statements access to data

Cursor Implementations ImplementationFeatures Transact-SQL Based on DECLARE CURSOR Implemented on server API Server Based on API functions in OLE DB and ODBC Implemented on server Client Implemented by Native Client ODBC and ADO Caches all result set rows on the client

Using Cursors Process of using a cursor Associate and define characteristics Populate the cursor Retrieve rows in the cursor Modify data if needed Close and deallocate the cursor DECLARE vend_cursor CURSOR FOR SELECT * FROM Purchasing.Vendor OPEN vend_cursor FETCH NEXT FROM vend_cursor CLOSE vend_cursor DEALLOCATE vend_cursor DECLARE vend_cursor CURSOR FOR SELECT * FROM Purchasing.Vendor OPEN vend_cursor FETCH NEXT FROM vend_cursor CLOSE vend_cursor DEALLOCATE vend_cursor

Demonstration: Working with Cursors In this demonstration, you will learn how to: Use cursors to work with result sets

Understanding Set-Based Logic SELECT ProductID, Purchasing.Vendor.VendorID, Name FROM Purchasing.ProductVendor JOIN Purchasing.Vendor ON (Purchasing.ProductVendor.VendorID = Purchasing.Vendor.VendorID) WHERE StandardPrice > $10 AND Name LIKE N'F%' GO SELECT ProductID, Purchasing.Vendor.VendorID, Name FROM Purchasing.ProductVendor JOIN Purchasing.Vendor ON (Purchasing.ProductVendor.VendorID = Purchasing.Vendor.VendorID) WHERE StandardPrice > $10 AND Name LIKE N'F%' GO Set-based logic SQL Server iterates through data Deals with results as a set instead of row-by-row

Demonstration: Using Set-Based Queries In this demonstration, you will learn how to: Use a set-based query to replace a cursor

Lesson 4: Dynamic SQL Introducing Dynamic SQL Using Dynamic SQL Considerations for Using Dynamic SQL

Introducing Dynamic SQL Dynamic SQL Allows query to be built using variables Places query into variable = = MAX(SalesOrderNumber) FROM Sales.SalesOrderHeader WHERE CustomerID = = MAX(SalesOrderNumber) FROM Sales.SalesOrderHeader WHERE CustomerID

Using Dynamic SQL Using sp_executesql sp_executesql = ] stmt [ {, data_type [ OUT | OUTPUT ][,...n]' } {, = ] 'value1' [,...n ] } ] sp_executesql = ] stmt [ {, data_type [ OUT | OUTPUT ][,...n]' } {, = ] 'value1' [,...n ] } ] Using EXECUTE [ { EXEC | EXECUTE } ] { = ] { module_name [ ;number ] } [ = ] { value [ OUTPUT ] | [ DEFAULT ] } ] [,...n ] [ WITH RECOMPILE ] } [;] [ { EXEC | EXECUTE } ] { = ] { module_name [ ;number ] } [ = ] { value [ OUTPUT ] | [ DEFAULT ] } ] [,...n ] [ WITH RECOMPILE ] } [;]

Considerations for Using Dynamic SQL Security Considerations: SQL Injection Security is checked for every object Performance Considerations: Query plan not reused frequently Use sp_executesql for best chance at plan reuse Performance related to complexity of query

Demonstration: Using Dynamic SQL In this demonstration, you will learn how to: Build and execute a query that uses dynamic SQL

Lesson 5: Maintaining Query Files What Are Versioning and Source Control? Features of Team Foundation Server 2008

What Are Versioning and Source Control? Versioning Provides a record of changes made Enables retrieval of previous versions Source Control Enables development teamwork Source files can be checked in/out and merged Other Benefits Provides a central location for source file storage Simplifies source file backup procedures

Features of Team Foundation Server 2008 Enabled support for Reporting Services on any server and any port Support for SQL Server 2008 New role for many operations activities

Lab: Using Advanced Querying Techniques Using Execution Plans Converting Data Types Implementing a Hierarchy Using Cursors and Set-Based Queries Logon information Virtual machineNY-SQL-01 User nameAdministrator Password Pa$$w0rd Estimated time: 60 minutes

Lab Scenario You are a Database Administrator at Adventure Works. As part of an effort to analyze database performance, the Senior Database Administrator has asked you to become familiar with query execution plans. In order to do this, you need to know how to view estimated and actual execution plans, as well as save execution plans and view them in XML format. You also need to familiarize yourself with implicit and explicit data type conversions. Also, you've been asked to create a hierarchy in the database for the Sales department. To do this, you will implement a table using the hierarchyid data type. You also need to determine whether database updates are more efficient using cursors or set-based queries. To do this, you will use a cursor to update ListPrice data and a set-based query to update StandardCost data in the Production.Product table to see how the two approaches compare.

Lab Review What is required for a conversion to the XML data type to succeed? How do you create the root node of a hierarchy? When using a cursor, how do you retrieve the next row in the result set?

Module Review and Takeaways Review Questions Common Issues and Troubleshooting Tips Best Practices

Course Evaluation