relational database normalization

Source: http://blog.csdn.net/robinjwong/article/details/185021951. Relational databaseRelational database refers to a database that uses a relational model to organize data.The relational model was first proposed by IBM researcher Dr. E.f.codd in 1970, and in the following d

Label:1. Relational databaseRelational database refers to a database that uses a relational model to organize data. The relational model was first proposed by IBM researcher Dr. E.f.codd in 1970, and in the following decades, the concept of

1. Relational database A relational database is a database that uses a relational model to organize data. The relational model was first proposed by IBM researcher Dr. E.f.codd in 1970

Acid principles for relational database compliance (1) A Atomic nature: All operations in a transaction, either done or done, the success of the transaction is the success of all operations in the transaction, as long as one operation fails, the entire transaction fails and needs to be rolled back. (2) C Consistency: The database should always be in a consistent

command line ha ... ）：8: After the environment is installed, you can manipulate the MongoDB database:Show DBS order to display a list of all data:The Execute DB command can display the current database object or collection:Run the use command to connect to a specified database:The syntax format for MongoDB database creation is as follows:User database name:The

usability and extensibility are better, The disadvantage is the implementation of complex and potential performance issues . do not share : any CPU can only access its own main memory and disk . The benefits are also scalability and availability, The disadvantage is to achieve complex and complex equalization . Hybrid : The system as a whole is a shared nothing schema, but the nodes may be inside other architectures. This blends the benefits of multiple ar

If these two conditions are met, it can be explained that the standard of the database is still relatively high. Of course, this is a two-generalities indicator. In order to meet the requirements of database design normalization, the following five requirements are generally required. Request One: Nullable columns should be avoided in the table. Although emp

generally allow people to write any information to While using data for COBOL programs, such as those familiar to any COBOL programmer, storing them in a relational database is similar to storing them in a flat file, the method stored in a flat file is not the best way to accomplish a task. Especially because you do not understand the difference between the two or fear change, but simply bring the idea o

Tags: another standalone COM operation junction DEP form BSP informationDatabase Normalization andClassic ThreeParadigm Redundancy causes multiple update exceptions, which are difficult to insert, update, and delete rows. 　　 Normalization (normalization) is a series of steps to reduce redundancy and contradiction by modifying tables. after each step, the

Specification | standardization | skill | data | Normalization skills of database Database Luke Chung President of FMS September 2002 Apply to: Microsoft®access Summary: This article provides developers with the skills to avoid certain problems when designing an Access table. This article applies to Microsoft Access databases (. mdb) and Microsoft Access proje

Tags: acid-based features This feature enables relational databases to be used in almost all of the typical banking systems but in Web applications of non-relational databasesThe most important feature of a relational database is transactional consistency : traditional relational