In a
relational database
A relational database (RDB) is a database based on the relational model of data, as proposed by E. F. Codd in 1970.
A Relational Database Management System (RDBMS) is a type of database management system that stores data in a structured for ...
, a row or "
record" or "
tuple
In mathematics, a tuple is a finite sequence or ''ordered list'' of numbers or, more generally, mathematical objects, which are called the ''elements'' of the tuple. An -tuple is a tuple of elements, where is a non-negative integer. There is o ...
", represents a single, implicitly structured
data
Data ( , ) are a collection of discrete or continuous values that convey information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted for ...
item in a
table
Table may refer to:
* Table (database), how the table data arrangement is used within the databases
* Table (furniture), a piece of furniture with a flat surface and one or more legs
* Table (information), a data arrangement with rows and column ...
. A database table can be thought of as consisting of rows and
columns
A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member ...
.
"What is a database row?"
Cory Janssen, Techopedia, retrieved 27 June 2014 Each row in a table represents a set of related data, and every row in the table has the same structure.
For example, in a table that represents companies, each row might represent a single company. Columns might represent things like company name, address, etc. In a table that represents ''the association'' of employees with departments, each row would associate one employee with one department.
The implicit structure of a row, and the meaning of the data values in a row, requires that the row be understood as providing a succession of data values, one in each column of the table. The row is then interpreted as a relvar composed of a set of tuple
In mathematics, a tuple is a finite sequence or ''ordered list'' of numbers or, more generally, mathematical objects, which are called the ''elements'' of the tuple. An -tuple is a tuple of elements, where is a non-negative integer. There is o ...
s, with each tuple consisting of the two items: the name of the relevant column and the value this row provides for that column.
Each column expects a data value of a particular type
Type may refer to:
Science and technology Computing
* Typing, producing text via a keyboard, typewriter, etc.
* Data type, collection of values used for computations.
* File type
* TYPE (DOS command), a command to display contents of a file.
* ...
.
For example, one column might require a unique identifier
An identifier is a name that identifies (that is, labels the identity of) either a unique object or a unique ''class'' of objects, where the "object" or class may be an idea, person, physical countable object (or class thereof), or physical mass ...
, another might require text representing a person's name, another might require an integer representing hourly pay in dollar
Dollar is the name of more than 25 currencies. The United States dollar, named after the international currency known as the Spanish dollar, was established in 1792 and is the first so named that still survives. Others include the Australian d ...
s.
References
{{DEFAULTSORT:Row (Database)
Data modeling
Relational model
Database management systems