ICDL Databases key terms

An organised collection of related data stored so that it can be accessed, managed and updated easily. In a relational database the data is held in tables that are linked together.

A database that stores data in multiple tables and links them through shared key fields rather than duplicating the same information in one large list.

The basic storage object in a database, made up of rows and columns, where each row is one record and each column is one field describing the same attribute.

One complete row in a table, holding all the field values that describe a single person, item, event or other entity.

One column in a table, representing a single attribute of the data such as a surname, a date or a price. Every field has a defined data type.

The setting that controls what kind of values a field may hold, for example text, number, currency, date/time or yes/no, and how those values are stored and displayed.

A field, or combination of fields, whose value is unique for every record in a table and never left empty, used to identify each row unambiguously.

A field in one table that holds the primary key value of a related record in another table, creating the link between the two tables.

A primary key made up of two or more fields used together, where the combination is unique even though each field on its own may repeat.

A structure the database keeps on one or more fields so that records can be found quickly without scanning the whole table. It speeds up searching but adds overhead when data changes.

A defined link between two tables based on matching key fields, which lets data from both tables be combined and keeps related records consistent.

A link where one record in the first table can match many records in the second table, but each record in the second table matches only one in the first.

A link where records in each table can match many records in the other. It is normally implemented using an extra junction table holding the keys of both tables.

A rule that stops a record being created or changed so that it points to a related record that does not exist, and blocks deleting a record that others still depend on.

Rules applied to a field to check that entered data is acceptable, such as a required entry, a range of allowed values or a list of permitted choices.

A pattern that controls the format in which data is typed into a field, for example forcing a date or phone number into a fixed layout of characters.

A saved request that selects, filters, sorts or calculates data from one or more tables and presents the result as a datasheet rather than stored data.

The most common type of query, which retrieves records that meet stated conditions and shows only the fields the designer chooses to include.

The condition or conditions entered in a query to limit which records are returned, for example only orders placed after a certain date or in one region.

A special character used in criteria to stand for unknown text, commonly an asterisk for any number of characters and a question mark for a single character.

A query that asks the user to type a value each time it runs, so the same saved query can be reused with different criteria without being redesigned.

A field created inside a query that works out a new value from existing fields, such as multiplying quantity by price, instead of storing that value in a table.

A function that summarises many records into one result, such as counting records or calculating a total, average, minimum or maximum of a field.

Structured Query Language, the standard text language used to create, retrieve and modify database data. Many database tools build SQL statements behind the scenes.

A screen layout built on a table or query that lets users view and enter records one at a time, with labels, controls and buttons instead of a raw datasheet.

Any item placed on a form or report, such as a text box, label, combo box, check box or command button, used to display data or accept user input.

A form embedded inside another form, usually showing the many-side records that belong to the record currently displayed in the main form.

A form control that offers a drop-down list of allowed values, so users pick an entry instead of typing it, which reduces typing errors.

A grid view of records and fields that looks like a spreadsheet and is used for entering or browsing data quickly rather than for a designed layout.

A formatted output built from a table or query, designed for printing or sharing, with headings, grouped sections, totals and page layout.

A band within a report that controls where content appears, such as the report header, page header, detail lines for each record, and the report footer.

Arranging report or query output so that records sharing a value are collected together under that value, often with a header and a summary total for each group.

Arranging records in a chosen order, such as alphabetically by surname or from newest to oldest date, without removing any records.

A temporary restriction applied to a table or form that hides records not matching a condition, without creating a saved query object.

Saving query, form or report output into another file format, such as a spreadsheet, PDF or text file, so it can be used outside the database.

A copy of the database file kept in a separate location so that data can be restored if the original is damaged, lost or corrupted.