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This article will explain in detail what the abnormal deletion operation means in the standardization of the relationship. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

The abnormal deletion operation in relational normalization refers to the deletion of data that should not be deleted, while normalization is a set of rules to solve the problems of data insertion, deletion and modification in the database. Relational normalization theory provides a theoretical standard to judge the quality of relational logical patterns, helps to predict the possible problems of relational patterns, and is an algorithmic tool to generate various patterns.

The exception of delete operation in relationship normalization refers to the deletion of data that should not be deleted.

Normalization is a set of rules to solve the problems of inserting, deleting and modifying exceptions in the database.

Normalization theory is a guide and tool for database logic design. The specific steps are as follows:

The main contents are as follows: (1) investigate the functional dependency of the relational model and determine the paradigm level. Analyze the relational patterns one by one, investigate whether there are partial functional dependencies, transfer functional dependencies, etc., and determine which paradigm they belong to.

(2) merge or decompose the relational schema. According to the application requirements, examine whether these relational schemas meet the requirements, so as to determine whether these schemas should be merged or decomposed, for example, relational schemas with the same master code can generally be merged. For non-BCNF relational schemas, it is necessary to examine whether "abnormal disadvantages" have an impact on practical applications. For those who are just queries and do not perform update operations, it is not necessary to standardize (decompose) the schemas. In practical applications, the higher the degree of standardization, the better. Sometimes the benefits of decomposition to eliminate update anomalies outweigh the losses compared with the low efficiency of frequent queries that require frequent natural joins. For those relational schemas that need to be decomposed, normalization methods and theories can be used for schema decomposition. Finally, the resulting relationship patterns are evaluated and adjusted to determine a more appropriate group of relationship patterns.

Relational normalization theory provides a theoretical standard to judge the pros and cons of relational logical patterns, helps to predict the problems that may occur in patterns, and is an algorithmic tool to generate various patterns, so it is a powerful tool for designers.

This is the end of the article on "what is the meaning of deletion operation exception in relationship standardization". I hope the above content can be helpful to you, so that you can learn more knowledge. If you think the article is good, please share it for more people to see.

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