Lesson 3
| Lesson 3 | Using Transact-SQL |
| Objective | Describe the basic features of Transact-SQL. |
Using Transact-SQL
You have probably heard of Transact-SQL, and perhaps you've wondered how it
differs from SQL. The answer is quite simple: Transact-SQL is Microsoft's implementation of SQL-92 with some significant enhancements. For
example, Transact-SQL provides commands for the following categories:
- Distributed queries-Transact-SQL allows queries to be run against multiple databases.
- Information schema views-Transact-SQL allows easy querying of metadata.
- Parallel queries -Transact-SQL allows faster execution of a query when the computer has more than one processor.
- Delayed name resolution-Transact-SQL allows SQL Server references to exist in stored procedures, triggers, and batch files, even though the object doesn't exist at he time of compilation.
- Enhanced cursor support-SQL Server 7.0's implementation of cursors exceeds the SQL-92 standard. (We'll look at cursors in greater detail in a later course in this series.)
- Job processing-Transact-SQL includes additional commands for processing SQL Server 7.0 jobs.
- Replication processing-Transact-SQL includes additional commands for processing replication.
- Enhanced security-Transact-SQL includes security commands that are not part of the SQL-92 standard.
- Full text support-Transact-SQL allows querying of indexed cataloged text.
As you go through this course and the other courses in this series, you probably will not be aware of whether a Transact-SQL statement is part of the SQL-92 standard. Actually, it doesn't matter. It's important to know only that the standard exists and that SQL Server 7 conforms to it. More important, SQL Server provides the Transact-SQL commands necessary to deal with SQL Server 7 on a daily basis. For example, Transact-SQL statements can contain variables and control-of-flow keywords. This allows Transact-SQL to act like a programming language. And Transact-SQL statements can be grouped together into a single procedure. In the next lesson, you'll learn how SQL Server 7 processes queries.