Appendix C Terms and Definitions

This appendix provides the terms and definitions discussed throughout the book.



Access database — An Access program developed with the Access Jet database engine.

Access project — An Access program that uses an SQL back end exclusively rather than local Jet elements.

Aggregate functions — Used to return a single value based on calculations on values stored in a column.

Alias — An alternate name for a table or column.

ALL — Keyword used to retrieve records from the main query that match all of the records in the subquery.

ALTER TABLE — Keywords used to modify table definitions in an existing table.

ANY — Keyword used to retrieve records from the main query that match any of the records in the subquery.

Arithmetic operators — Used to perform mathematical calculations.

AS — Keyword used to assign an alternate name to a column or table.

ASC — Keyword used to sort column values in ascending order.

ASP — Active Server Pages. Visual Basic code used in web development for web pages that need to access a back-end database or that have processing on the page.

Attribute — The characteristics of an entity.



Cartesian product — When each row in one table is multiplied by the total number of rows in another table.

Clause — A segment of an SQL statement that assists in the selection and manipulation of data.

Client — A single-user computer that interfaces with a multi-ple-user server.

Client/server database system — A database system that divides processing between client computers and a database server.

Column — A field within a table.

Comparison operators — Used to perform comparisons among expressions.

Concatenation — Merging values or columns together.

Constraints — Used to restrict values that can be inserted into a field and to establish referential integrity.

Correlated subquery — Executes once for each record a referenced query returns.

CREATE TABLE — Keywords used to instruct the database to create a new table.

CREATE VIEW — Keywords used to instruct the DBMS to create a new view.



Data modeling — The process of organizing and documenting the data that will be stored in a database.

Data type — Specifies the type of data a column can store.

Database — A collection of electronically stored organized files that relate to one another.

Database management system (DBMS) Used to create, manage, and secure relational databases.

Date and time functions — Used to manipulate values based on the time and date.

DELETE — Used to remove records from a table.

DESC — Keyword used to sort column values in descending order.

DISALLOW NULL — Keywords used to prevent null data from being inserted into a column.

DISTINCT — Keyword used to display unique values in a column.

DISTINCTROW — Keyword used to exclude records based on the entire duplicate records, not just duplicate fields.

DROP VIEW — Keywords used to delete a view.



Entity — Any group of events, persons, places, or things used to represent how data is stored.

ERD model — The representation of data in terms of entities and relationships.

EXISTS — Keyword used to check for the existence of a value in the subquery.

Expression — Any data type that returns a value.



Field — Equivalent to a column.

Field size — Specifies the maximum number of characters that a cell in a column can hold.

File — A collection of similar records.

Foreign key — A column in a table that links records of the table to the records of another table.



GROUP BY clause — Used with aggregate functions to combine groups of records into a single functional record.



HAVING clause — Used with the GROUP BY clause to set conditions on groups of data calculated from aggregate functions.

HTML — Hypertext Markup Language.



IGNORE NULL — Used to cause null data in a table to be ignored for an index.

IIS — Internet Information Services.

IN — Keyword used to compare values in a column against column values in another table or query.

INDEX — Keyword used to sort and save the values of a column in a different location on the computer with a pointer pointing to the presorted records.

INNER JOIN — Keywords used to instruct the DBMS to combine matching values from two tables.

INSERT statement — Used to add records to a table.



Keys — Columns of a table with record values that are used as a link from other tables.

Keywords — Reserved words used within SQL statements.



LEFT JOIN — Keywords used to select every record from the table specified to the left of the LEFT JOIN keywords.

Logical operators —Used to test for the truth of some condition.



Microsoft Access — A desktop database management system used to create, manage, and secure relational databases.



Non-correlated subquery — Executes once since it contains no reference to an outside query.

Normalization — A three-step technique used to ensure that all tables are logically linked together and that all fields in a table directly relate to the primary key.

NOT — Keyword used to match any condition opposite of the one defined.

NULL — Keyword used to indicate no value.



ON — Keyword used to specify a condition.

ORDER BY clause — Used to sort retrieved records in descending or ascending order.



Parameter query — A query that enables the user to set the criteria for selecting records at run time by filling in a dialog box.

PRIMARY — Keyword used to designate a column as a primary key.

Primary key — A column in a table that uniquely identifies every record in a table.



Qualification — Used to match a column with a specific table.

Query — A question or command posed to the database.



Recordset — A collection of records in Visual Basic programming.

Referential integrity — A system of rules used to ensure that relationships between records in related tables are valid.

Relational database — A collection of two or more tables related by key values.

Relationship — An association between entities.

Result set — Records retrieved from the database.

RIGHT JOIN — Keyword used to select every record from the table specified to the right of the RIGHT JOIN keywords.

Row — A record within a table.



SELECT statement — Used to retrieve records from the database.

Self join — Used to join a table to itself.

Server — A multiple-user computer that provides shared database connection, interfacing, and processing services.

SOME — Keyword used to retrieve records from the main query that match any of the records in the subquery.

Statements — Keywords combined with data to form a database query.

String functions — Used to manipulate strings of character(s).

Structured Query Language (SQL) — A nonprocedural database programming language used within DBMSs to create, manage, and secure relational databases.

Subquery — A query linked to another query enabling values to be passed among queries.

Syntax — A series of rules that state how SQL script must be scripted.



Table — A two-dimensional file that contains rows and columns.

Temporary table — A table that encompasses the result of a saved SELECT statement.

TOP — Keyword used to display records that fall at the top or bottom of a range that is specified by an ORDER BY clause.

TOP PERCENT — Keywords used to display a percentage of records that fall at the top or bottom of a range that is specified by an ORDER BY clause.



UNION — Keyword used to combine records from two queries while excluding duplicate records.

UNION ALL — Keywords used to combine records from two queries while including duplicate records.

UNIQUE — Keyword used to ensure that only unique, non-repeating values are inserted in an indexed column.

UPDATE statement — Used to update records in a table.



VBA — Visual Basic for Applications. The flavor of Visual Basic incorporated in Access and in much of the Microsoft Office suite.

View — A saved query that queries one or more tables.



WHERE clause — Used to filter retrieved records.

Wildcard characters — Special characters used to match parts of a value.

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