Glossary

alias Another name or term for a table or column.

ANSI American National Standards Institute. This institute is responsible for issuing standards for a variety of topics. This is where the SQL standard is published.

application A set of menus, forms, reports, and code that performs a business function and typically uses a database.

buffer An area in memory for editing or execution of SQL.

cartesian product The result of not joining tables in the WHERE clause of an SQL statement. When tables in a query are not joined, every row in one table is paired with every row in all other tables.

client The client is typically a PC, but it can be server that is dependent on another computer for data, services, or processing. A client application enables a client machine to communicate with a server.

column A part of a table that has a name and a specific data type.

COMMIT Makes changes to data permanent.

composite index An index that is composed of two or more columns.

condition Search criteria in a query’s WHERE clause that evaluates to TRUE or FALSE.

constant A value that does not change.

constraint Restrictions on data that are enforced at the data level.

cursor A work area in memory that uses SQL statements to typically perform row-based operations against a set of data.

data dictionary Another name for the system catalog. See system catalog.

data type Defines data as a type, such as number, date, or character.

database A collection of data that is typically organized into sets of tables.

DBA Database administrator. An individual who manages a database.

DDL Data Definition Language. The part of the SQL syntax that specifically deals with defining database objects such as tables, views, and functions.

default A value used when no specification has been made.

distinct Unique; used in the SELECT clause to return unique values.

DML Data Manipulation Language. The part of the SQL syntax that specifically deals with manipulating data, such as that used in update statements.

domain An object that is associated with a data type to which constraints may be attached; similar to a user-defined type.

DQL Data Query Language. The part of the SQL syntax that specifically deals with querying data using the SELECT statement.

end user Users whose jobs require them to query or manipulate data in the database. The end user is the individual for which the database exists.

field Another name for a column in a table. See column.

foreign key One or more columns whose values are based on the primary key column values in another table.

full table scan The search of a table from a query without the use of an index.

function An operation that is predefined and can be used in an SQL statement to manipulate data.

GUI Graphical user interface. This is what an application interface is typically referred to when it provides graphical elements for the user to interact with.

host The computer on which a database is located.

index Pointers to table data that make access to a table more efficient.

JDBC Java Database Connectivity. Software that allows a Java program to communicate with a database to process data.

join Combines data from different tables by linking columns. Used in the WHERE clause of an SQL statement.

key A column or columns that identify rows of a table.

normalization Designing a database to reduce redundancy by breaking large tables into smaller, more manageable ones.

NULL value A value that is unknown.

objects Elements in a database, such as triggers, tables, views, and procedures.

ODBC Open Database Connectivity. Software that allows for standard communication with a database. ODBC is typically used for inter-database communication between different implementations and for communication between a client application and a database.

operator A reserved word or symbol that performs an operation, such as addition or subtraction.

optimizer Internal mechanism of the database (consists of rules and code) that decides how to execute an SQL statement and return an answer.

parameter A value or range of values to resolve a part of an SQL statement or program.

primary key A specified table column that uniquely identifies rows of the table.

privilege Specific permissions that are granted to users to perform a specific action in the database.

procedure A set of instructions that are saved for repeated calling and execution.

public A database user account that represents all database users.

query An SQL statement that retrieves data from a database.

record Another name for a row in a table. See row.

referential integrity Ensures the existence of every value of a column from a parent that is referenced in another table. This ensures that the data in your database is consistent. Referential integrity is normally used between two tables, but in some tables it can be used so that a table references itself. A self-referenced table is referred to as a recursive relationship. In databases, this is often referred to as a foreign key relationship.

relational database A database that is organized into tables that consist of rows, which contain the same sets of data items, where tables in the database are related to one another through common keys.

role A database object that is associated with a group of system or object privileges, used to simplify security management.

ROLLBACK A command that undoes all transactions since the last COMMIT or SAVEPOINT command was issued.

row Sets of records in a table.

savepoint A specified point in a transaction to which you can roll back or undo changes.

schema A set of related objects in a database owned by a single database user.

security The process of ensuring that data in a database is fully protected at all times.

SQL Structured Query Language designed for use with databases and used to manage the data within those systems.

stored procedure SQL code that is stored in a database and ready to execute.

subquery A SELECT statement embedded within another SQL statement.

synonym Another name given to a table or view.

syntax for SQL A set of rules that shows mandatory and optional parts of an SQL statement’s construction.

system catalog Collection of tables or views that contain information about the database.

table The basic logical storage unit for data in a relational database.

transaction One or more SQL statements that are executed as a single unit.

trigger A stored procedure that executes upon specified events in a database, such as before or after an update of a table.

user-defined type A data type that is defined by a user, which can be used to define table columns.

variable A value that does not remain constant.

view A database object that is created from one or more tables and can be used the same as a table. A view is a virtual table that has no storage requirements of its own.