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📄 Contents

  1. SQL Server Reference Guide
  2. Introduction
  3. SQL Server Reference Guide Overview
  4. Table of Contents
  5. Microsoft SQL Server Defined
  6. SQL Server Editions
  7. SQL Server Access
  8. Informit Articles and Sample Chapters
  9. Online Resources
  10. Microsoft SQL Server Features
  11. SQL Server Books Online
  12. Clustering Services
  13. Data Transformation Services (DTS) Overview
  14. Replication Services
  15. Database Mirroring
  16. Natural Language Processing (NLP)
  17. Analysis Services
  18. Microsot SQL Server Reporting Services
  19. XML Overview
  20. Notification Services for the DBA
  21. Full-Text Search
  22. SQL Server 2005 - Service Broker
  23. Using SQL Server as a Web Service
  24. SQL Server Encryption Options Overview
  25. SQL Server 2008 Overview
  26. SQL Server 2008 R2 Overview
  27. SQL Azure
  28. The Utility Control Point and Data Application Component, Part 1
  29. The Utility Control Point and Data Application Component, Part 2
  30. Microsoft SQL Server Administration
  31. The DBA Survival Guide: The 10 Minute SQL Server Overview
  32. Preparing (or Tuning) a Windows System for SQL Server, Part 1
  33. Preparing (or Tuning) a Windows System for SQL Server, Part 2
  34. Installing SQL Server
  35. Upgrading SQL Server
  36. SQL Server 2000 Management Tools
  37. SQL Server 2005 Management Tools
  38. SQL Server 2008 Management Tools
  39. SQL Azure Tools
  40. Automating Tasks with SQL Server Agent
  41. Run Operating System Commands in SQL Agent using PowerShell
  42. Automating Tasks Without SQL Server Agent
  43. Storage – SQL Server I/O
  44. Service Packs, Hotfixes and Cumulative Upgrades
  45. Tracking SQL Server Information with Error and Event Logs
  46. Change Management
  47. SQL Server Metadata, Part One
  48. SQL Server Meta-Data, Part Two
  49. Monitoring - SQL Server 2005 Dynamic Views and Functions
  50. Monitoring - Performance Monitor
  51. Unattended Performance Monitoring for SQL Server
  52. Monitoring - User-Defined Performance Counters
  53. Monitoring: SQL Server Activity Monitor
  54. SQL Server Instances
  55. DBCC Commands
  56. SQL Server and Mail
  57. Database Maintenance Checklist
  58. The Maintenance Wizard: SQL Server 2000 and Earlier
  59. The Maintenance Wizard: SQL Server 2005 (SP2) and Later
  60. The Web Assistant Wizard
  61. Creating Web Pages from SQL Server
  62. SQL Server Security
  63. Securing the SQL Server Platform, Part 1
  64. Securing the SQL Server Platform, Part 2
  65. SQL Server Security: Users and other Principals
  66. SQL Server Security – Roles
  67. SQL Server Security: Objects (Securables)
  68. Security: Using the Command Line
  69. SQL Server Security - Encrypting Connections
  70. SQL Server Security: Encrypting Data
  71. SQL Server Security Audit
  72. High Availability - SQL Server Clustering
  73. SQL Server Configuration, Part 1
  74. SQL Server Configuration, Part 2
  75. Database Configuration Options
  76. 32- vs 64-bit Computing for SQL Server
  77. SQL Server and Memory
  78. Performance Tuning: Introduction to Indexes
  79. Statistical Indexes
  80. Backup and Recovery
  81. Backup and Recovery Examples, Part One
  82. Backup and Recovery Examples, Part Two: Transferring Databases to Another System (Even Without Backups)
  83. SQL Profiler - Reverse Engineering An Application
  84. SQL Trace
  85. SQL Server Alerts
  86. Files and Filegroups
  87. Partitioning
  88. Full-Text Indexes
  89. Read-Only Data
  90. SQL Server Locks
  91. Monitoring Locking and Deadlocking
  92. Controlling Locks in SQL Server
  93. SQL Server Policy-Based Management, Part One
  94. SQL Server Policy-Based Management, Part Two
  95. SQL Server Policy-Based Management, Part Three
  96. Microsoft SQL Server Programming
  97. An Outline for Development
  98. Database
  99. Database Services
  100. Database Objects: Databases
  101. Database Objects: Tables
  102. Database Objects: Table Relationships
  103. Database Objects: Keys
  104. Database Objects: Constraints
  105. Database Objects: Data Types
  106. Database Objects: Views
  107. Database Objects: Stored Procedures
  108. Database Objects: Indexes
  109. Database Objects: User Defined Functions
  110. Database Objects: Triggers
  111. Database Design: Requirements, Entities, and Attributes
  112. Business Process Model Notation (BPMN) and the Data Professional
  113. Business Questions for Database Design, Part One
  114. Business Questions for Database Design, Part Two
  115. Database Design: Finalizing Requirements and Defining Relationships
  116. Database Design: Creating an Entity Relationship Diagram
  117. Database Design: The Logical ERD
  118. Database Design: Adjusting The Model
  119. Database Design: Normalizing the Model
  120. Creating The Physical Model
  121. Database Design: Changing Attributes to Columns
  122. Database Design: Creating The Physical Database
  123. Database Design Example: Curriculum Vitae
  124. NULLs
  125. The SQL Server Sample Databases
  126. The SQL Server Sample Databases: pubs
  127. The SQL Server Sample Databases: NorthWind
  128. The SQL Server Sample Databases: AdventureWorks
  129. The SQL Server Sample Databases: Adventureworks Derivatives
  130. UniversalDB: The Demo and Testing Database, Part 1
  131. UniversalDB: The Demo and Testing Database, Part 2
  132. UniversalDB: The Demo and Testing Database, Part 3
  133. UniversalDB: The Demo and Testing Database, Part 4
  134. Getting Started with Transact-SQL
  135. Transact-SQL: Data Definition Language (DDL) Basics
  136. Transact-SQL: Limiting Results
  137. Transact-SQL: More Operators
  138. Transact-SQL: Ordering and Aggregating Data
  139. Transact-SQL: Subqueries
  140. Transact-SQL: Joins
  141. Transact-SQL: Complex Joins - Building a View with Multiple JOINs
  142. Transact-SQL: Inserts, Updates, and Deletes
  143. An Introduction to the CLR in SQL Server 2005
  144. Design Elements Part 1: Programming Flow Overview, Code Format and Commenting your Code
  145. Design Elements Part 2: Controlling SQL's Scope
  146. Design Elements Part 3: Error Handling
  147. Design Elements Part 4: Variables
  148. Design Elements Part 5: Where Does The Code Live?
  149. Design Elements Part 6: Math Operators and Functions
  150. Design Elements Part 7: Statistical Functions
  151. Design Elements Part 8: Summarization Statistical Algorithms
  152. Design Elements Part 9:Representing Data with Statistical Algorithms
  153. Design Elements Part 10: Interpreting the Data—Regression
  154. Design Elements Part 11: String Manipulation
  155. Design Elements Part 12: Loops
  156. Design Elements Part 13: Recursion
  157. Design Elements Part 14: Arrays
  158. Design Elements Part 15: Event-Driven Programming Vs. Scheduled Processes
  159. Design Elements Part 16: Event-Driven Programming
  160. Design Elements Part 17: Program Flow
  161. Forming Queries Part 1: Design
  162. Forming Queries Part 2: Query Basics
  163. Forming Queries Part 3: Query Optimization
  164. Forming Queries Part 4: SET Options
  165. Forming Queries Part 5: Table Optimization Hints
  166. Using SQL Server Templates
  167. Transact-SQL Unit Testing
  168. Index Tuning Wizard
  169. Unicode and SQL Server
  170. SQL Server Development Tools
  171. The SQL Server Transact-SQL Debugger
  172. The Transact-SQL Debugger, Part 2
  173. Basic Troubleshooting for Transact-SQL Code
  174. An Introduction to Spatial Data in SQL Server 2008
  175. Performance Tuning
  176. Performance Tuning SQL Server: Tools and Processes
  177. Performance Tuning SQL Server: Tools Overview
  178. Creating a Performance Tuning Audit - Defining Components
  179. Creating a Performance Tuning Audit - Evaluation Part One
  180. Creating a Performance Tuning Audit - Evaluation Part Two
  181. Creating a Performance Tuning Audit - Interpretation
  182. Creating a Performance Tuning Audit - Developing an Action Plan
  183. Understanding SQL Server Query Plans
  184. Performance Tuning: Implementing Indexes
  185. Performance Monitoring Tools: Windows 2008 (and Higher) Server Utilities, Part 1
  186. Performance Monitoring Tools: Windows 2008 (and Higher) Server Utilities, Part 2
  187. Performance Monitoring Tools: Windows System Monitor
  188. Performance Monitoring Tools: Logging with System Monitor
  189. Performance Monitoring Tools: User Defined Counters
  190. General Transact-SQL (T-SQL) Performance Tuning, Part 1
  191. General Transact-SQL (T-SQL) Performance Tuning, Part 2
  192. General Transact-SQL (T-SQL) Performance Tuning, Part 3
  193. Performance Monitoring Tools: An Introduction to SQL Profiler
  194. Performance Tuning: Introduction to Indexes
  195. Performance Monitoring Tools: SQL Server 2000 Index Tuning Wizard
  196. Performance Monitoring Tools: SQL Server 2005 Database Tuning Advisor
  197. Performance Monitoring Tools: SQL Server Management Studio Reports
  198. Performance Monitoring Tools: SQL Server 2008 Activity Monitor
  199. The SQL Server 2008 Management Data Warehouse and Data Collector
  200. Performance Monitoring Tools: Evaluating Wait States with PowerShell and Excel
  201. Practical Applications
  202. Choosing the Back End
  203. The DBA's Toolbox, Part 1
  204. The DBA's Toolbox, Part 2
  205. Scripting Solutions for SQL Server
  206. Building a SQL Server Lab
  207. Using Graphics Files with SQL Server
  208. Enterprise Resource Planning
  209. Customer Relationship Management (CRM)
  210. Building a Reporting Data Server
  211. Building a Database Documenter, Part 1
  212. Building a Database Documenter, Part 2
  213. Data Management Objects
  214. Data Management Objects: The Server Object
  215. Data Management Objects: Server Object Methods
  216. Data Management Objects: Collections and the Database Object
  217. Data Management Objects: Database Information
  218. Data Management Objects: Database Control
  219. Data Management Objects: Database Maintenance
  220. Data Management Objects: Logging the Process
  221. Data Management Objects: Running SQL Statements
  222. Data Management Objects: Multiple Row Returns
  223. Data Management Objects: Other Database Objects
  224. Data Management Objects: Security
  225. Data Management Objects: Scripting
  226. Powershell and SQL Server - Overview
  227. PowerShell and SQL Server - Objects and Providers
  228. Powershell and SQL Server - A Script Framework
  229. Powershell and SQL Server - Logging the Process
  230. Powershell and SQL Server - Reading a Control File
  231. Powershell and SQL Server - SQL Server Access
  232. Powershell and SQL Server - Web Pages from a SQL Query
  233. Powershell and SQL Server - Scrubbing the Event Logs
  234. SQL Server 2008 PowerShell Provider
  235. SQL Server I/O: Importing and Exporting Data
  236. SQL Server I/O: XML in Database Terms
  237. SQL Server I/O: Creating XML Output
  238. SQL Server I/O: Reading XML Documents
  239. SQL Server I/O: Using XML Control Mechanisms
  240. SQL Server I/O: Creating Hierarchies
  241. SQL Server I/O: Using HTTP with SQL Server XML
  242. SQL Server I/O: Using HTTP with SQL Server XML Templates
  243. SQL Server I/O: Remote Queries
  244. SQL Server I/O: Working with Text Files
  245. Using Microsoft SQL Server on Handheld Devices
  246. Front-Ends 101: Microsoft Access
  247. Comparing Two SQL Server Databases
  248. English Query - Part 1
  249. English Query - Part 2
  250. English Query - Part 3
  251. English Query - Part 4
  252. English Query - Part 5
  253. RSS Feeds from SQL Server
  254. Using SQL Server Agent to Monitor Backups
  255. Reporting Services - Creating a Maintenance Report
  256. SQL Server Chargeback Strategies, Part 1
  257. SQL Server Chargeback Strategies, Part 2
  258. SQL Server Replication Example
  259. Creating a Master Agent and Alert Server
  260. The SQL Server Central Management System: Definition
  261. The SQL Server Central Management System: Base Tables
  262. The SQL Server Central Management System: Execution of Server Information (Part 1)
  263. The SQL Server Central Management System: Execution of Server Information (Part 2)
  264. The SQL Server Central Management System: Collecting Performance Metrics
  265. The SQL Server Central Management System: Centralizing Agent Jobs, Events and Scripts
  266. The SQL Server Central Management System: Reporting the Data and Project Summary
  267. Time Tracking for SQL Server Operations
  268. Migrating Departmental Data Stores to SQL Server
  269. Migrating Departmental Data Stores to SQL Server: Model the System
  270. Migrating Departmental Data Stores to SQL Server: Model the System, Continued
  271. Migrating Departmental Data Stores to SQL Server: Decide on the Destination
  272. Migrating Departmental Data Stores to SQL Server: Design the ETL
  273. Migrating Departmental Data Stores to SQL Server: Design the ETL, Continued
  274. Migrating Departmental Data Stores to SQL Server: Attach the Front End, Test, and Monitor
  275. Tracking SQL Server Timed Events, Part 1
  276. Tracking SQL Server Timed Events, Part 2
  277. Patterns and Practices for the Data Professional
  278. Managing Vendor Databases
  279. Consolidation Options
  280. Connecting to a SQL Azure Database from Microsoft Access
  281. SharePoint 2007 and SQL Server, Part One
  282. SharePoint 2007 and SQL Server, Part Two
  283. SharePoint 2007 and SQL Server, Part Three
  284. Querying Multiple Data Sources from a Single Location (Distributed Queries)
  285. Importing and Exporting Data for SQL Azure
  286. Working on Distributed Teams
  287. Professional Development
  288. Becoming a DBA
  289. Certification
  290. DBA Levels
  291. Becoming a Data Professional
  292. SQL Server Professional Development Plan, Part 1
  293. SQL Server Professional Development Plan, Part 2
  294. SQL Server Professional Development Plan, Part 3
  295. Evaluating Technical Options
  296. System Sizing
  297. Creating a Disaster Recovery Plan
  298. Anatomy of a Disaster (Response Plan)
  299. Database Troubleshooting
  300. Conducting an Effective Code Review
  301. Developing an Exit Strategy
  302. Data Retention Strategy
  303. Keeping Your DBA/Developer Job in Troubled Times
  304. The SQL Server Runbook
  305. Creating and Maintaining a SQL Server Configuration History, Part 1
  306. Creating and Maintaining a SQL Server Configuration History, Part 2
  307. Creating an Application Profile, Part 1
  308. Creating an Application Profile, Part 2
  309. How to Attend a Technical Conference
  310. Tips for Maximizing Your IT Budget This Year
  311. The Importance of Blue-Sky Planning
  312. Application Architecture Assessments
  313. Transact-SQL Code Reviews, Part One
  314. Transact-SQL Code Reviews, Part Two
  315. Cloud Computing (Distributed Computing) Paradigms
  316. NoSQL for the SQL Server Professional, Part One
  317. NoSQL for the SQL Server Professional, Part Two
  318. Object-Role Modeling (ORM) for the Database Professional
  319. Business Intelligence
  320. BI Explained
  321. Developing a Data Dictionary
  322. BI Security
  323. Gathering BI Requirements
  324. Source System Extracts and Transforms
  325. ETL Mechanisms
  326. Business Intelligence Landscapes
  327. Business Intelligence Layouts and the Build or Buy Decision
  328. A Single Version of the Truth
  329. The Operational Data Store (ODS)
  330. Data Marts – Combining and Transforming Data
  331. Designing Data Elements
  332. The Enterprise Data Warehouse — Aggregations and the Star Schema
  333. On-Line Analytical Processing (OLAP)
  334. Data Mining
  335. Key Performance Indicators
  336. BI Presentation - Client Tools
  337. BI Presentation - Portals
  338. Implementing ETL - Introduction to SQL Server 2005 Integration Services
  339. Building a Business Intelligence Solution, Part 1
  340. Building a Business Intelligence Solution, Part 2
  341. Building a Business Intelligence Solution, Part 3
  342. Tips and Troubleshooting
  343. SQL Server and Microsoft Excel Integration
  344. Tips for the SQL Server Tools: SQL Server 2000
  345. Tips for the SQL Server Tools – SQL Server 2005
  346. Transaction Log Troubles
  347. SQL Server Connection Problems
  348. Orphaned Database Users
  349. Additional Resources
  350. Tools and Downloads
  351. Utilities (Free)
  352. Tool Review (Free): DBDesignerFork
  353. Aqua Data Studio
  354. Microsoft SQL Server Best Practices Analyzer
  355. Utilities (Cost)
  356. Quest Software's TOAD for SQL Server
  357. Quest Software's Spotlight on SQL Server
  358. SQL Server on Microsoft's Virtual PC
  359. Red Gate SQL Bundle
  360. Microsoft's Visio for Database Folks
  361. Quest Capacity Manager
  362. SQL Server Help
  363. Visual Studio Team Edition for Database Professionals
  364. Microsoft Assessment and Planning Solution Accelerator
  365. Aggregating Server Data from the MAPS Tool

In the last tutorial, I explained primary and foreign keys, and in previous tutorials on tables I explained the use of NULL values. I will continue the table discussion here, with an explanation of constraints.

It's fairly simple to describe a table constraint — it's just like the English use of the word, which means “to prevent or constrict”. In the case of a SQL Server database table, constraints are rules you create to specify what kind of data is allowed in a table — specifically, a field in a table.

Whether you design databases or program against them, database integrity is absolutely essential. It's not just about making sure a certain table has data in it; it's about ensuring that the data throughout the system doesn't cause a program to crash or a result to be ambiguous. In fact, it’s better for data not to make it into a table than for that data to make it into the database but be incorrect. Think about a transaction at your local Automatic Teller Machine (ATM). You would rather a transaction fail (and tell you that it failed) than for the wrong amount of money to be withdrawn.

Constraints enable SQL Server to implement this integrity. There are several classes of constraints, which I’ll explain in a moment. By layering them intelligently, you can maintain the integrity of the database as a whole.

Most constraints are column-based, meaning that they are declared and enforced on a single column at a time. One, in particular, is declared and enforced on a table, and I’ll explain that one in a moment.

SQL Server uses several classes of constraints. I've already shown you the basics of three of them, but I'll explain them a bit further in this article. The primary classes are:

  • Primary Key
  • Foreign Key
  • Not Null
  • Unique
  • Check

I will briefly explain each of these constraints.

Primary Key

I explained the primary key constraint in a previous article. A primary key is a column that makes a row unique. In fact, this is a constraint. In other words, you are saying that only one row can have this particular value. So that “constrains” the values you can enter for that column.

To declare the primary key constraint, you use the PRIMARY KEY directive after the column definition when you create a table, or with the ALTER TABLE command if the table is already there. Here's an example of each:

CREATE TABLE test
(
PrimaryKeyColumnName smallint
  IDENTITY(1,1)
  PRIMARY KEY 
)
and:
ALTER TABLE TEST ADD 
PrimaryKeyColumnName INT IDENTITY
CONSTRAINT PrimaryKeyName PRIMARY KEY 

Keep in mind that you can't violate the rules for creating a primary key on a table if it's already got data. In the example above, I created a new column for the key, but if you use a current column as a key, it has to have unique values on it.

There's a qualifier you can use when you create this constraint (and others) called WITH NOCHECK. This qualifier applies the rule without first verifying that the affected data is within the rule — but you have to be careful here.

In the case of the primary key, if you have a repeated value in a column, applying the primary key constraint on that column the statement will fail. However, if you apply the constraint with the WITH NOCHECK statement, SQL Server will apply the constraint (and do it very quickly, I might add); but the very next time you load or alter data, that change will fail and the table will lock.

If that happens, you'll have to change the table by removing the primary key and then fix the data. So the short story is that you shouldn't use the WITH NOCHECK qualifier unless you're certain the data works with the constraint first. Primary keys enforce entity integrity, meaning that a column is guaranteed to be unique. The system simply won't let you enter duplicate data in a primary key column.

Foreign Key

I also explained foreign key constraints in the last tutorial. The foreign key "points" to a primary key of another table, guaranteeing that you can't enter data into a table unless the referenced table has the data already.

You can use this constraint in situations such as an order-entry system, where the item being sold in a transaction must exist in inventory first, or have a price in a pricing table, or both. It helps you enforce relationships between tables.

Primary keys must be unique, but foreign keys don't. In fact, if you think about the situations I mentioned above, you'll realize that the values in a foreign key column almost always involve repeated values. Think about a purchase order. You might have several items on a single purchase order. So you might create a table to hold the “Purchase Order” itself, and then another table to hold the various line items that belong to a particular purchase order. To do that you create a primary key in the purchase order table, and a foreign key field in the purchase order line item table pointing back to the primary key of the purchase order table. If you implement the constraints this way, you won’t allow a line item to be created if there is no purchase order first. That follows standard business rules for a database.

You can create a foreign key either when you create the table or after the fact, with the same restrictions that I mentioned earlier regarding the primary key.

Here is the way to create a foreign key when you create a table:

CREATE TABLE test
(
foreignkeycolumnname smallint
FOREIGN KEY REFERENCES tablename(PrimaryKeyColumnName) 
)
And here's the syntax example for adding the foreign key constraint after the fact:
ALTER TABLE Orders ADD CONSTRAINT
 FK_Orders_Clients FOREIGN KEY
 (
 ClientID
 ) REFERENCES Clients
 (
 ClientID
 ) ON UPDATE CASCADE
  ON DELETE CASCADE

Notice the qualifiers at the end of the statement. They provide for the updating and deletion of the child records from the parent table operations. Without these qualifiers, you're not able to delete a record from a table if records in another have a foreign key reference to the primary key in the first. You need to decide fairly early in your design process whether you'll allow users to delete child records when you delete a parent.

You may think that this is a great idea — but you may not want to unilaterally remove records like that. For instance, recall the example I mentioned earlier, regarding the order-entry system. If you delete an item from inventory because you're not carrying it any more, you certainly don't want to delete all the sales you'd recorded in the past for that item! In that case, it's better to have the program fail. Instead of deleting what you've carried as inventory, a better process might be to create a field in the parent table that indicates whether the item is current.

To recap, a foreign key enforces relational integrity, by guaranteeing the relationship between tables.

Not Null

I've explained NULL values several times, but the definition bears repeating: a NULL is not zero, or empty, or blank. A NULL is a special value type, and means that the value is not known (yet).

So how does that fit in with constraints? Well, if you set a value of NOT NULL when you create or alter a table column, then the program or user must enter a value. This is normally a really good process. It doesn't make a lot of sense to have a database that's filled with "I don't know" values.

If you do constrain values to NOT NULL, it's often a good practice to provide a default value for that column. Here's the syntax for that:

CREATE TABLE test
(
ColumnName VARCHAR(30)
NOT NULL
DEFAULT('Value Not Entered')
)

Use nulls wisely!

Unique

The unique constraint forces the values in a column to be unique. But isn't that what a primary key does? Yes, but there are two important distinctions for this type of constraint. The first is that you can have more than one unique constraint. You can only have one primary key. The other advantage is that the unique constraint doesn't count NULL values; if you have one, it's OK.

Here's the syntax for a unique constraint:

CREATE TABLE test
(
ColumnName VARCHAR(30)
UNIQUE
)

And if you already have the table in place:

ALTER TABLE test ADD NewColumnName VARCHAR(20) NULL 
 CONSTRAINT ConstraintName UNIQUE

Notice that I've named the last constraint. Certain constraints, such as this one and the next, can have a name that can be re-used, so that you only have to create the constraint once.

Check

The check constraint is very useful, as it allows you to force the values that can be used in a field. This restriction is called the "domain" of values.

Take a look at the following syntax:

CREATE TABLE test
(
ColumnName int
CHECK (ColumName < 30)
)

Notice that this check constraint isn't named, and that it ensures the value of ColumnName will be less than 30. Here's another example:

CONSTRAINT CK_emp_id 
CHECK (emp_id LIKE 
 '[A-Z][A-Z][A-Z][1-9][0-9][0-9][0-9][0-9]' )

This example from Books Online shows you the complexity you can build using the CHECK constraint. The brackets indicate the range, and the OR qualifier sets an alternate range. In other words, there are nine characters that you can set: the first can be a letter from A to Z, the next must be an A to Z, and so on. You can see the fourth character must be the number 1 through 9, the next 0 through 9 and so on.

I have a lot more to say about constraints, but I'll save that for the design discussion. See you next time, when we'll look at data types.

InformIT Articles and Sample Chapters

From one of my favorite books, Sams Teach Yourself SQL in 24 Hours, read more about Integrity Constraints in the article Mananging Database Objects.

Books and eBooks

And here’s a link to the latest edition of that book, Sams Teach Yourself SQL in 24 Hours.

Online Resources

You can read more about SQL Server Constraints from Books Online.

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  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020