query language
Học thuậtThân thiện
Definition
Noun: A specialized computer language used to request and retrieve information from a database or other organized data source. It consists of a set of commands and procedural operators that invoke specific functions to be executed, allowing users to ask questions (queries) about the data.
Usage
A query language is used to communicate with a database management system. It provides a structured way to search, filter, insert, update, and delete data. The core action is to formulate a precise question or command that the system can process.
Examples
- SQL (Structured Query Language) is the most common query language for relational databases.
- To generate the report, the analyst wrote a complex command in the database's query language.
- The new system supports a query language that allows for very specific searches within the document archive.
Advanced Usage
- Declarative vs. Procedural: Some query languages (like SQL) are primarily declarative, meaning the user specifies data is wanted, not to get it. The reference context describes a language with "procedural operators," which implies instructions on to execute the query.
- Query Optimization: A key advanced concept is how the database engine interprets and executes the commands of a query language in the most efficient way possible.
Variants and Related Words
- Query (n/v): The question or request for data itself; or the act of making such a request.
- Example: She ran a query to find all customers from London.
- SQL (Structured Query Language): The standard language for relational database management systems.
- QL (abbreviation): A common abbreviation for "query language."
Synonyms
- Search Language
- Data Query Language (DQL)
- Database Language
Related Phrases
- Query a database: The action of using a query language to interrogate a database.
- Example: You need to query the database to get the latest sales figures.
- Query syntax: The set of rules that defines the correct structure of commands in a query language.
- Example: An error in your query syntax will cause the command to fail.
Noun
- a source language consisting of procedural operators that invoke functions to be executed