dbms支持哪几种数据模型_DBMS数据库模型
dbms支持哪几种数据模型
DBMS数据库模型 (DBMS Database Models)
A Database model defines the logical design and structure of a database and defines how data will be stored, accessed and updated in a database management system. While the Relational Model is the most widely used database model, there are other models too:
数据库模型定义了数据库的逻辑设计和结构，并定义了如何在数据库管理系统中存储，访问和更新数据。 虽然关系模型是使用最广泛的数据库模型，但也有其他模型：
- Hierarchical Model 层次模型
- Network Model 网络模型
- Entity-relationship Model 实体关系模型
- Relational Model 关系模型
层次模型 (Hierarchical Model)
This database model organises data into a tree-like-structure, with a single root, to which all the other data is linked. The heirarchy starts from the Root data, and expands like a tree, adding child nodes to the parent nodes.
该数据库模型将数据组织成具有单个根的树状结构，所有其他数据都链接到该树状结构。 层次结构从“ 根”数据开始，并像树一样扩展，将子节点添加到父节点。
In this model, a child node will only have a single parent node.
在此模型中，子节点将只有一个父节点。
This model efficiently describes many real-world relationships like index of a book, recipes etc.
该模型有效地描述了许多现实世界中的关系，例如书的索引，食谱等。
In hierarchical model, data is organised into tree-like structure with one one-to-many relationship between two different types of data, for example, one department can have many courses, many professors and of-course many students.
在分层模型中，数据被组织成树状结构，在两种不同类型的数据之间具有一对多的关系，例如，一个部门可以开设许多课程，许多教授，当然还有许多学生。
网络模型 (Network Model)
This is an extension of the Hierarchical model. In this model data is organised more like a graph, and are allowed to have more than one parent node.
这是层次模型的扩展。 在此模型中，数据的组织方式更像图，并且可以具有多个父节点。
In this database model data is more related as more relationships are established in this database model. Also, as the data is more related, hence accessing the data is also easier and fast. This database model was used to map many-to-many data relationships.
在此数据库模型中，随着在此数据库模型中建立更多的关系，数据之间的关系更加密切。 另外，由于数据之间的关联性更高，因此访问数据也变得更加轻松快捷。 该数据库模型用于映射多对多数据关系。
This was the most widely used database model, before Relational Model was introduced.
在引入关系模型之前，这是使用最广泛的数据库模型。
实体关系模型 (Entity-relationship Model)
In this database model, relationships are created by dividing object of interest into entity and its characteristics into attributes.
在此数据库模型中，通过将感兴趣的对象划分为实体并将其特征划分为属性来创建关系。
Different entities are related using relationships.
不同的实体使用关系进行关联。
E-R Models are defined to represent the relationships into pictorial form to make it easier for different stakeholders to understand.
定义了ER模型以图形形式表示关系，以使不同的涉众更容易理解。
This model is good to design a database, which can then be turned into tables in relational model(explained below).
该模型非常适合设计数据库，然后可以将其转换为关系模型中的表（如下所述）。
Let's take an example, If we have to design a School Database, then Student will be an entity with attributes name, age, address etc. As Address is generally complex, it can be another entity with attributes street name, pincode, city etc, and there will be a relationship between them.
让我们举个例子，如果我们必须设计一个学校数据库，那么学生将是一个具有名称，年龄，地址等属性的实体 。由于地址通常很复杂，因此它可以是具有街道名称，密码，城市等属性的另一个实体 ，他们之间会有关系。
Relationships can also be of different types. To learn about E-R Diagrams in details, click on the link.
关系也可以是不同的类型。 要详细了解ER图 ，请单击链接。
关系模型 (Relational Model)
In this model, data is organised in two-dimensional tables and the relationship is maintained by storing a common field.
在此模型中，数据被组织在二维表中，并且通过存储公共字段来维护关系。
This model was introduced by E.F Codd in 1970, and since then it has been the most widely used database model, infact, we can say the only database model used around the world.
该模型由EF Codd于1970年引入，从那时起，它一直是使用最广泛的数据库模型，事实上，可以说是全世界唯一使用的数据库模型。
The basic structure of data in the relational model is tables. All the information related to a particular type is stored in rows of that table.
关系模型中数据的基本结构是表。 与特定类型有关的所有信息都存储在该表的行中。
Hence, tables are also known as relations in relational model.
因此，表也被称为关系模型关系 。
In the coming tutorials we will learn how to design tables, normalize them to reduce data redundancy and how to use Structured Query language to access data from tables.
在接下来的教程中，我们将学习如何设计表，对其进行规范化以减少数据冗余以及如何使用结构化查询语言访问表中的数据。
dbms支持哪几种数据模型