relational algebra是什么意思，relational algebra的意思翻译、用法、同义词、例句

常用词典

[数] 关系代数

例句

The lookup is an example of the Rails 3 relational algebra.

查询是 Rails 3 关系代数的一个示例。

In relational databases, an operation in relational algebra.

在关系数据库中，关系代数中一种操作。

Rails 3 incorporates relational algebra, a DSL designed to express queries.

Rails 3 合并了 relational algebra，这是专门设计用于表示查询的 DSL。

The derived relational algebra operators are widely used in the relational database query languages.

关系代数的派生算子在关系数据库查询语言中得到了广泛应用。

Similarly, based on the medium set theory MS, the medium relational algebra can extend the capability of relational algebra.

同样地，中介关系代数以中介集合论MS为基础，扩充了关系代数的功能。

网络扩展资料

Relational algebra is a theoretical framework used for querying data stored in relational databases. It consists of a set of operations that can be applied to a set of relations (tables) to produce a new relation (table).

Usage

Relational algebra is used by database developers and administrators to design and manipulate relational databases. It provides a formal and mathematical way of expressing queries that can be used across different database management systems.

Example sentences

The relational algebra operation JOIN is used to combine two tables based on a common column.
Relational algebra allows us to manipulate data in a structured and consistent way.

Explanation

Relational algebra consists of several operations, including SELECT, PROJECT, UNION, INTERSECTION, DIFFERENCE, CROSS PRODUCT, and JOIN. These operations can be combined to create complex queries that retrieve specific data from a database.

SELECT is used to retrieve rows from a table that meet a given condition.
PROJECT is used to select specific columns from a table.
UNION is used to combine two tables into a single table, eliminating duplicate rows.
INTERSECTION is used to retrieve only the rows that appear in both tables.
DIFFERENCE is used to retrieve all the rows from one table that do not appear in another table.
CROSS PRODUCT is used to combine every row from one table with every row from another table.
JOIN is used to combine two tables based on a common column.

Synonyms and Antonyms

There are no direct synonyms or antonyms for relational algebra, as it is a specific term used in the context of relational databases.

中文解释

关系代数是一种用于查询存储在关系数据库中的数据的理论框架。它由一组操作组成，这些操作可以应用于一组关系（表）以产生一个新关系（表）。

关系代数由几个操作组成，包括“选择”、“投影”、“联合”、“交集”、“差异”、“笛卡尔积”和“连接”。这些操作可以组合成复杂的查询，从数据库中检索特定的数据。

“选择”用于检索满足给定条件的表中的行。“投影”用于从表中选择特定的列。“联合”将两个表合并成一个表，消除重复行。“交集”用于检索仅出现在两个表中的行。“差异”用于检索一个表中未出现在另一个表中的所有行。“笛卡尔积”用于将一个表的每一行与另一个表的每一行组合。“连接”用于基于共同列组合两个表。

没有关系代数的直接同义词或反义词，因为它是在关系数据库上下文中使用的特定术语。

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