Row (database)
Encyclopedia
In the context of a relational database
, a row—also called a record or tuple
—represents a single, implicitly structured data
item in a table
. In simple terms, a database table can be thought of as consisting of rows and columns
or fields. 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 would represent a single company. Columns might represent things like company name, company street address, whether the company is publicly held, its VAT number
, etc.. In a table that represents the association of employees with departments, each row would associate one employee with one department.
In a less formal usage, e.g. for a database which is not formally relational, a record is equivalent to a row as described above, but is not usually referred to as a row.
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
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. For example, one column might require a unique identifier
, another might require text representing a person's name, another might require an integer representing hourly pay in cent
s.
Relational database
A relational database is a database that conforms to relational model theory. The software used in a relational database is called a relational database management system . Colloquial use of the term "relational database" may refer to the RDBMS software, or the relational database itself...
, a row—also called a record or tuple
Tuple
In mathematics and computer science, a tuple is an ordered list of elements. In set theory, an n-tuple is a sequence of n elements, where n is a positive integer. There is also one 0-tuple, an empty sequence. An n-tuple is defined inductively using the construction of an ordered pair...
—represents a single, implicitly structured data
Data
The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...
item in a table
Table (database)
In relational databases and flat file databases, a table is a set of data elements that is organized using a model of vertical columns and horizontal rows. A table has a specified number of columns, but can have any number of rows...
. In simple terms, a database table can be thought of as consisting of rows and columns
Column (database)
In the context of a relational database table, a column is a set of data values of a particular simple type, one for each row of the table. The columns provide the structure according to which the rows are composed....
or fields. 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 would represent a single company. Columns might represent things like company name, company street address, whether the company is publicly held, its VAT number
Value added tax identification number
A value added tax identification number or VAT identification number is an identifier used in many countries, including the countries of the European Union, for value added tax purposes....
, etc.. In a table that represents the association of employees with departments, each row would associate one employee with one department.
In a less formal usage, e.g. for a database which is not formally relational, a record is equivalent to a row as described above, but is not usually referred to as a row.
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
Relvar
In relational databases, a relvar is a term coined by C. J. Date as an abbreviation for the concept of relation variable, which is the actual term used by the inventor of the relational model, E. F. Codd, regarding the same concept...
composed of a set of tuple
Tuple
In mathematics and computer science, a tuple is an ordered list of elements. In set theory, an n-tuple is a sequence of n elements, where n is a positive integer. There is also one 0-tuple, an empty sequence. An n-tuple is defined inductively using the construction of an ordered pair...
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. For example, one column might require a unique identifier
Identifier
An identifier is a name that identifies either a unique object or a unique class of objects, where the "object" or class may be an idea, physical [countable] object , or physical [noncountable] substance...
, another might require text representing a person's name, another might require an integer representing hourly pay in cent
Cent (currency)
In many national currencies, the cent is a monetary unit that equals 1⁄100 of the basic monetary unit. Etymologically, the word cent derives from the Latin word "centum" meaning hundred. Cent also refers to a coin which is worth one cent....
s.
| Column 1 | Column 2 | |
|---|---|---|
| Row 1 | Row 1, Column 1 | Row 1, Column 2 |
| Row 2 | Row 2, Column 1 | Row 2, Column 2 |
| Row 3 | Row 3, Column 1 | Row 3, Column 2 |
See also
- Column (database)Column (database)In the context of a relational database table, a column is a set of data values of a particular simple type, one for each row of the table. The columns provide the structure according to which the rows are composed....
- Record (computer science)Record (computer science)In computer science, a record is an instance of a product of primitive data types called a tuple. In C it is the compound data in a struct. Records are among the simplest data structures. A record is a value that contains other values, typically in fixed number and sequence and typically indexed...