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Pandas supports hierarchical indices with multiple values per data point. An index with this structure, called a "MultiIndex", allows a single DataFrame to represent multiple dimensions, similar to a pivot table in Microsoft Excel. [4]: 147–148 Each level of a MultiIndex can be given a unique name.
In computer science, a database cursor is a mechanism that enables traversal over the records in a database. Cursors facilitate processing in conjunction with the traversal, such as retrieval, addition and removal of database records. The database cursor characteristic of traversal makes cursors akin to the programming language concept of iterator.
A hierarchical database model is a data model in which the data is organized into a tree-like structure. The data are stored as records which is a collection of one or more fields . Each field contains a single value, and the collection of fields in a record defines its type .
A database index is a data structure that improves the speed of data retrieval operations on a database table at the cost of additional writes and storage space to maintain the index data structure. Indexes are used to quickly locate data without having to search every row in a database table every time said table is accessed.
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
List of Relational Database Management Systems (Alphabetical Order) Name License 4th Dimension: Proprietary Access Database Engine (formerly known as Jet Database Engine) Proprietary Actian Zen (PSQL) (formerly known as Pervasive PSQL) Proprietary Adabas D: Proprietary Airtable: Proprietary Altibase: Proprietary Amazon Aurora: Proprietary ...
The purpose of an inverted index is to allow fast full-text searches, at a cost of increased processing when a document is added to the database. [2] The inverted file may be the database file itself, rather than its index. It is the most popular data structure used in document retrieval systems, [3] used on a large scale for example in search ...
The MultiDimensional eXpressions (MDX) language provides a specialized syntax for querying and manipulating the multidimensional data stored in OLAP cubes. [1] While it is possible to translate some of these into traditional SQL, it would frequently require the synthesis of clumsy SQL expressions even for very simple MDX expressions.