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A tabular data card proposed for Babbage's Analytical Engine showing a key–value pair, in this instance a number and its base-ten logarithm. A key–value database, or key–value store, is a data storage paradigm designed for storing, retrieving, and managing associative arrays, and a data structure more commonly known today as a dictionary or hash table.
JSON (JavaScript Object Notation, pronounced / ˈ dʒ eɪ s ən / or / ˈ dʒ eɪ ˌ s ɒ n /) is an open standard file format and data interchange format that uses human-readable text to store and transmit data objects consisting of name–value pairs and arrays (or other serializable values).
Query by Example (QBE) is a database query language for relational databases. It was devised by Moshé M. Zloof at IBM Research during the mid-1970s, in parallel to the development of SQL . [ 1 ] It is the first graphical query language, using visual tables where the user would enter commands, example elements and conditions.
Object stores are similar to key–value stores in two respects. First, the object identifier or URL (the equivalent of the key) can be an arbitrary string. [40] Second, data may be of an arbitrary size. There are, however, a few key differences between key–value stores and object stores. First, object stores also allow one to associate a ...
An Array is a JavaScript object prototyped from the Array constructor specifically designed to store data values indexed by integer keys. Arrays, unlike the basic Object type, are prototyped with methods and properties to aid the programmer in routine tasks (for example, join , slice , and push ).
Riak is a distributed NoSQL key-value data store based on CRDTs. [29] League of Legends uses the Riak CRDT implementation for its in-game chat system, which handles 7.5 million concurrent users and 11,000 messages per second. [30] Bet365 stores hundreds of megabytes of data in the Riak implementation of OR-Set. [31]
Sequelize, Node.js ORM tool for Postgres, MySQL, MariaDB, SQLite, DB2, Microsoft SQL Server, and Snowflake; Typeorm, Typescript/Javascript scalable ORM tool; MikroORM, TypeScript ORM based on Data Mapper, Unit of Work and Identity Map patterns. Supports PostgreSQL, MySQL, SQLite (including libSQL), MongoDB, and MariaDB
DQL statements are used for performing queries on the data within schema objects. The purpose of DQL commands is to get the schema relation based on the query passed to it. Although often considered part of DML, the SQL SELECT statement is strictly speaking an example of DQL. When adding FROM or WHERE data manipulators to the SELECT statement ...