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1, Design table Premise: the design table should first follow the three paradigms as needed Review 3NF: 1NF – > column is the smallest atom that cannot be subdivided (avoid duplication);2NF – > primary key dependency (unique);3NF – > eliminate the transfer dependency (establish the primary foreign key Associati ...

📚 preface SQL language has a history of more than 40 years. Since it was applied, it has been almost everywhere. Every payment record we consume, every user information we collect and every message we send will be stored in the database or its related products, and the language to manipulate the database is SQL! SQL is almost a necessar ...

The resource usage statistics of each sql statement in the database is often the most troublesome part and the most effective way to locate the problem. In addition, the resource usage can help the DBA to confirm whether the business concurrency increases, whether the hardware resources meet the existing requirements, and whether the parameters ...

join query What connection query? In the actual development, in most cases, the data is not queried from a single table. Generally, multiple tables are queried jointly to get the final result. In actual development, a business usually corresponds to multiple tables. For example, students and classes have to save at least two tables. Of cour ...

Theory and test of oracle materialized view 1. Materialized view (1) Basic concepts of oracle materialized view Materialized views first need to create materialized view logs, oracle Create a materialized view log table based on the materialized view log created by the user. The name of the materialized view log table is mlog$_Followed by t ...

❤️ Hello, I'm Gauss squirrel club. Welcome to study~ ❤️ ‍ Described in the previous article "9.3 role management" In this chapter, we introduce the wonderful contents related to "9.4 object permission management" in Chapter 9 security management source code analysis. 9.4 object permission management Permission manag ...