I am going to wrap up my discussion of LOGON TRIGGERS. The number and types of database triggers available to database administrators has increased over the years as the Microsoft SQL Server database engine has matured. There are now triggers for execution after both DDL and DML modifications. These triggers can be classified as AFTER – TSQL code to be executed after an action or INSTEAD OF – TSQL code to be executed in lue of a action. Triggers are commonly used in following tasks: Auditing data changes by place…
Tag: TABLE
Database Files – Part 1
A Microsoft SQL Server database is composed of at least two operating system files: a primary data file and a transaction log file. I am going to be talking about how to define databases with multiple files tonight. There are three types of operating system files. PRIMARY data file is the starting point of the database and is a pointer to any other data files that are allocated. A extension of .mdf is used to identify these files. This data file can contains system tables and user defined objects as…
Temporary Tables – Part 3
Today, I am going to talk about table variables. In general, TSQL variables are defined by using the DECLARE key word and preceeding the variable name with a @ sign. Table variables are created by using the TABLE key word just after the variable name. The declaration following this key word includes column definitions — names, data types, and constraints. The only constraint types allowed in the declaration are PRIMARY KEY, UNIQUE, NULL, and CHECK. Indexes are a bi-product of a PRIMARY and UNIQUE constraints. The scope of a table…