What are the three elements of data in a database?

Generally speaking, any data model is a set of strictly defined concepts. These concepts must accurately describe the static characteristics, dynamic characteristics and integrity constraints of the system. Therefore, a data model usually consists of three elements: data structure, data operation and integrity constraints.

1) data structure

Data structure is used to describe the static characteristics of database system.

A data structure is a collection of object types studied. These objects are components of a database, and they are related to data types, contents and attributes, such as fields, attributes and relationships in a relational model. Once a data structure is defined, it usually does not change.

2) Data manipulation

Data manipulation is used to describe the dynamic characteristics of a database system.

Data operation refers to the set of operations allowed on instances (values) of various objects (types) in the database, including operations and related operation rules. There are two main types of database operations: query and update (including insert, delete and modify). The data model must define the exact meaning of these operations, operation symbols, operation rules (such as priority) and the language in which the operations are implemented.

3) Integrity constraints

The constraint condition of data is a set of integrity rules. Integrity rules are the constraints and storage rules of data and their relationships in a given data model, which are used to limit the state and change of the database according to the data model to ensure the correctness, validity and compatibility of the data. In the relational model, general relationships must meet two conditions: entity integrity and referential integrity.