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preface When creating a table, you can add corresponding constraints to the fields of the table. The purpose of adding constraints is to ensure the legitimacy, validity and integrity of the data in the table. Common constraints nameexplainNon NULL constraint (not null)The field of the constraint cannot be NULLUnique constraintConstrained ...

Project resource requirements   VMVare15 resource link: https://pan.baidu.com/s/1cVzeKjqu0Cmp4qMRDbFx8Q Extraction code: tdn4   CentOS7 image file link: https://pan.baidu.com/s/14QyfiXYYObdynswJlOoI1g Extraction code: 6cxp   oracle11 Linux version link: https://pan.baidu.com/s/16hWmzGudLjUEpkRzHAOGZw Extraction code: y34w &e ...

get ready The Maven project is directly used here. The tool used is idea, the connection is Oracle (of course, the operation of mysql is almost the same). I hope you can do the code here, so as to ensure harvest. Create Maven project Create a new project, select Maven, select the jdk version, and do not use the skeleton Enter the groupI ...

What's more Experiment 1 of 2020 database system of Shandong University Experiment 2 of 2020 database system of Shandong University Experiment 3 of 2020 database system of Shandong University Experiment 4 of 2020 database system of Shandong University Experiment 5 of 2020 database system of Shandong University Experiment 6 of 2020 database sys ...

1 what is a stored procedure (a set of sql statements compiled in advance and stored in the database) 1.1 Stored Procedure In a large database system, a set of SQL statements to complete specific functions are stored in the database and called again after the first compilation. There is no need to compile again. The user calls the stored proc ...

Common database objects What is a sequence? Sequence: a database object that can be used by multiple users to generate unique values Automatically provide unique values Shared object It is mainly used to provide primary key values Loading sequence values into memory can improve access efficiency CREATE SEQUENCE statement Define sequence: CRE ...

Installing Oracle on Linux requires some preparation, such as dependency packages, groups and users, kernel parameters, resource constraints, directories, environment variables, and so on. This series of articles is to share the author's practical records when he first came into contact with and studied Linux. It mainly includes some theo ...

This article is MySQL HeatWave Quickstart (quick start) A sequel to. I watched it today MySQL HeatWave user manual , it has changed from more than 60 pages to 96 pages, and Autopilot, object storage persistence layer and other contents have been added. Basic concepts: HeatWave is memory array, distributed and sharedHeatWave Cluster includes ...

We have learned how to use the Spring Security framework. In this chapter, we need to apply the Spring Security framework to the background system for permission control. Its essence is authentication and authorization. To carry out authentication and authorization, we need to support the seven tables i ...

preface Tianjin Shenzhou General Data Technology Co., Ltd. (hereinafter referred to as "Shenzhou general company") is subordinate to China Aerospace Science and Technology Corporation (CASC). Is engaged in the domestic database, big data solutions and data mining analysis product research and development of professional companies. The ...