Introduction to the tables and indexes of Oracle objects

For a traditional relational database management system (RDBMS), such as Oracle, MySQL, etc., are stored and retrieved data in the database, in Oracle, a schema to represent a logical data structure or a collection of schema objects, schema objects are user-created, Used to directly reference data in a database, where the most important objects are tables and indexes.

Tables are the basic unit of data organization in a database, a table describes an entity, such as a students table, we use a table name (students) and some columns to set an entity, each column represents a student's property, and the table, which represents a collection of rows, Each line records a specific student's information.

The index is an optional data structure in the database, and we can create indexes on one or more columns in the table to improve the retrieval performance of the data, and the index is to quickly navigate to the data we want to retrieve. In Oracle, indexes are logically and physically independent of data, so we can delete and create indexes without any effect on other indexes or data in the table.

In Oracle, there are many types of tables, relational tables, object tables, and tables that are organized according to organizational characteristics, organized tables, index organization tables, external tables, and so on.

Indexes are divided into primary key indexes, unique indexes, non-null indexes, normal indexes, bitmap indexes, and so on.

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Introduction to the tables and indexes of Oracle objects