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Disabling Constraints and Triggers
Constraints are valuable tools for maintaining data integrity in databases. However, there are times when it is convenient to disable one or more of them to perform tasks such as data synchronization with an offline database. When SQL Server replication is used to synchronize data between databases, individual objects can be told to withhold enforcement during replication.
For example, when a foreign key constraint is defined using the NOT FOR REPLICATION statement, SQL Server will not enforce the constraint during the replication process. In fact, the NOT FOR REPLICATION statement can be used directly in T-SQL statements that define foreign key constraints, check constraints, identities, and triggers. For those who use SQL Server replication, using the NOT FOR REPLICATION statement on the appropriate objects is a good option. However, if you are instead performing a manual synchronization of your data, another option is to disable the constraints and triggers manually.
Manual synchronization is often performed in online/offline applications where there is a subset of the data to be synchronized and where greater control over how the data is synchronized is required. In this month's column, I will discuss when it might be advantageous to manually disable and enable constraints, what kinds of problems this can solve, and some tricks to help you out..
SQL Server CLR Integration Part 1: Security
Identifying NHibernate-Related Bottlenecks through Performance Monitoring
Using Asymmetric Encryption and Digital Signatures in a SQL Server 2005 Database
In this article we start with a look at the T-SQL commands for performing asymmetric encryption and decryption. Next, we discuss using digital signatures as a means for ensuring the integrity of the encrypted data. This article concludes with an ASP.NET 2.0 website example that ties together the lessons learned throughout this article series. Specifically, the database used by this ASP.NET application stores customer information with the customer's credit card information encrypted. An ASP.NET page provides a means to view the sensitive information in plaintext as well as a means to add new customers to the database with the credit card information properly encrypted.
Use Table-Valued Functions as Arrays in SQL Server
Using Symmetric Encryption in a SQL Server 2005 Database
As the attacks in which hackers use become more and more sophisticated, and the programs in which they attack become increasingly complex, encryption is becoming the last line of defense in database management system (DBMS) security.
In this article we will look at how, specifically, to encrypt the data in a SQL Server 2005 database using symmetric encryption techniques. We'll start with examining the facilities for managing keys in SQL Server and then explore symmetric encryption in SQL Server 2005.
An Overview of Cryptographic Systems and Encrypting Database Data
As the attacks in which hackers use become more and more sophisticated, and the programs in which they attack become increasingly complex, encryption is becoming the last line of defense in database management system (DBMS) security. Since Microsoft announced their Trustworthy Computing security initiatives four years ago, the industry has been waiting to see how these initiatives would be implemented in upcoming products. With the introduction of Microsoft's newest DBMS, SQL Server 2005, it does indeed seem as though they have provided what they have promised.
What follows is a two-part article series that provides an in-depth examination of encrypting data in SQL Server 2005. In this article we will exploring key challenges facing database systems and the motivations for providing robust encryption mechanisms directly within the database system. We will also look at encryption fundamentals and SQL Server 2005's encryption capabilities.