RDBMS和ORDBMS之间的差异

RDBMS vs odbms

关系数据库管理系统（RDBMS）是基于关系模型的数据库管理系统（DBMS）。目前正在使用的最流行的DBMS是RDMS。对象相关数据库（ORDBMS）也是DBMS，它扩展了RDBMS，以支持更广泛的应用程序类别，并尝试在关系和面向对象的范式之间创建桥梁。

正如前面提到的,RDBMS是基于relational model and data in a RDMS are stored in the form of related tables. So, a relational database can simply be seen as a collection of one or more relations or tables with columns and rows. Each column corresponds to an attribute of the relation and each row corresponds to a record that consists of data values for an entity. RDMSs are developed by extending hierarchical and the network models, which were two previous database systems. Main elements of a RDMS are the concepts of relational integrity and normalization. These concepts are based on the 13 rules for a relational system developed by Ted Codd. Following three important fundamentals should be followed by a RDMS. Firstly, all information must be held in the form of a table. Secondly, each value found in the table columns should not repeat and finally the use of Standard Query Language (SQL). The biggest advantage of RDBMSs is its easiness for users to create access and extend data. After a database is created, user can add new data categories to the database without changing the existing application. There are some notable limitations in RDBMSs also. One limitation is that their lack of efficiency when working with languages other than SQL and also the fact that all the information must be in tables where relationships between entities are defined by values. Further, RDMSs do not have enough storage area to handle data such as images, digital audio and video. Currently most of the dominant DBMSs such as IBM’s DB2 family, Oracle, Microsoft’s Access and SQL Server are actually RDMS.

如前所述，ORDBMS在RDM和面向对象的数据库（OODBMS）之间提供了中间立场。您可以简单地说ORDBMS将面向对象的前端放在RDBMS上。当应用程序与OrdBMS通信时，通常会像将数据存储为对象一样。然后，ORDBMS将将对象信息转换为带有行和列的数据表，并处理将其存储在RDBMS中的数据。此外，当检索数据时，它将通过重新组装简单数据来返回一个复杂的对象。ORDBMS的最大优点是，它提供了在RDBMS格式和OODBMS格式之间转换数据的方法，因此从面向对象的语言中，程序员无需编写代码即可在两种格式之间进行转换，并且数据库访问很容易。

即使RDBM和ORDBM都是DBMS，它们与应用程序的交互方式不同。使用RDBMS的应用程序在存储复杂的数据时必须进行额外的工作，而ORDBM固有地为此提供了支持。但是由于数据格式之间的内部转换，因此可以降低ORDBMS的性能。因此，选择一个而不是另一个需要存储/管理的数据。