A subquery places one query inside another one. The second query resides somewhere within the WHERE clause of a SELECT statement. One or more values returned by the subquery are used by the main query to return the results to the user Subquery: A query that is embedded in a main, or parent, query and used [...]
SQL
SQL*Plus Worksheet
Oracle Enterprise Manager (OEM) : A GUI tool that allows access, maintenance, and monitoring of multiple databases or services within a single application. If Oracle Enterprise Manager (OEM) is installed, another variation of SQL*Plus, called SQL*Plus Worksheet, is available to the DBA. Here’s the OEM Login dialog box: SQL*Plus Worksheet supports all the commands that standard [...]
iSQL*Plus
With iSQL*Plus, you connect to the database indirectly via a very “lightweight” middle tier. The iSQL*Plus tool is essentially the web-enabled version of SQL*Plus, with a few restrictions, which we will cover shortly. It is implemented as part of a three-tier Oracle environment, although iSQL*Plus could very well run on the same machine as [...]
SQL*Plus
SQL*Plus has been around as long as the Oracle RDBMS itself. It is the most basic tool available for connecting to the database and executing queries against the tables in a database. On Unix systems, it can be run in character-based mode, even on a dumb terminal connected to the Unix system via a serial [...]
Implementing Data Integrity
If checks are not applied while defining and creating tables, the data stored in the tables can become redundant. For example, if you do not store the data about all the employees with complete address details, then the data would not be useful. Similarly, if a database used by the Human Resources department stores employee [...]
System Databases in SQL Server 2005
System Databases are the standard databases that exist in every instance of SQL Server 2005.These databases contain a specific set of tables that are used to store server- specific configurations, templates for other databases. In addition, these databases contain a temporary storage area required to query the database. SQL Server 2005 contains the following system [...]
SQL, Query Optimization, and Query Processing
It might seem a bit patronizing to call attention to the query word in Structured Query Language (SQL). It is crucial, though, that you as a PC database developer or administrator understand the special significance of the word in SQL Server, even in SQL Server Desktop Engine, which will replace Jet as the default Access [...]
