Chapter 6. Glossary

This section lists some database-related terms and their meanings.

Column

The set of all instances of a given field from all records in a table .

Database

One or more large structured sets of persistent data, usually associated with software to update and query the data. A simple database might be a single file containing many records , each of which contains the same set of fields where each field is a certain fixed width.

Data Modelling

The product of the database design process which aims to identify and organize the required data logically and physically.

Data Warehousing

A database, often remote, containing recent snapshots of corporate data. Planners and researchers can use this database freely without worrying about slowing down day-to-day operations of the production database.

ETL

Extraction, Transforming and Loading - the process of maintaining and transforming data into and out of a relational database.

Foreign key

A column in a database table containing values that are also found in some primary key column (of a different table). By extension, any reference to entities of a different type.

Some RDBMSs allow a column to be explicitly labelled as a foreign key and only allow values to be inserted if they already exist in the relevant primary key column.

Identifying Relationship

Where the key of the parent table is a subset of the key of the child table.

JDBC

Java DataBase Connectivity, an unofficial acronym for the "java.sql" package of functionality used to access relational databases from programs written in the Java programming language.

Key

A value used to identify a record in a database, derived by applying some fixed function to the record. The key is often simply one of the fields (a column if the database is considered as a table with records being rows, see " key field "). Alternatively the key may be obtained by applying some function, e.g. a hash function , to one or more of the fields. The set of keys for all records forms an index . Multiple indexes may be built for one database depending on how it is to be searched.

Primary key

The candidate key selected as being most important for identifying a body of information (an entity, object or record ).

Record (row)

One or more structured sets of persistent data, usually associated with software to update and query the data. A simple database might be a single file containing many records , each of which contains the same set of fields where each field is a certain fixed width.

SQL

Originally SEQUEL and still pronounced that way by many practitioners, SQL is the Standard Query Language; a unified language for creating queries that is accepted (with some variations) by all modern relational databases.

Table

A collection of records in a relational database .

Some of these terms are from FolDoc, "The Free On-line Dictionary of Computing", http://www.foldoc.org/, Editor Denis Howe.