Programming VIP

1, Create library and table classes create database a;//Create database //Create table create table name( Field name char(10), Field name 2 char(10) ) drop Command is also the method of use 2, Modify table data alter sentence //Delete column alter table student drop column Field name; //Add column alter table student add column Field na ...

Article catalogue I Create a spring project using IDEA II Establish project structure III Create database IV Import pom dependencies V Writing pojo entity classes Vi Write dao layer VII Write service layer VIII Write controller layer IX Write usermapper XML Mapping File X Write yml configuration information Xi Write front page XII ...

Detailed explanation of Mysql index What is an index? 1. Index An index is the directory of a table. You can find the index position in the directory before finding the content, so as to quickly locate the query data. For indexes, they are saved in additional files. **2. * * index is a data structure specially used to help users query data ...

1, Introduction to Tidb 1. What is TiDB TiDB is an open-source distributed relational database independently designed and developed by PingCAP company. It is an integrated distributed database product that supports both online transaction processing and online analytical processing (HTAP). It has horizontal expansion or reduction, financi ...

Database (warehouse)Model (warehouse design drawing) fields: CharField，IntegerField，FloatField，DateTimeField，             OneToOneField，ManyToManyField，Foreignkey fields parameter: max_length,choices Instance (goods)QuerySet query set (package) List like objects Indexable, sliced, in (instance in queryset) Database connection Dja ...

There are two ways to realize read-write separation and data segmentation Method 1: middle tier agent (mycat) System application ----- > intermediate agent ----- > Database Method 2: the client mode (sharding JDBC) only needs to introduce the jar package of the client Difference: mycat is the server agent and sharding JDBC is the c ...

day28 Today's content Basic concepts of JDBCquick get startA detailed explanation of interfaces and classes in JDBC JDBC Concept: Java Database Connectivity (JDBC) is an application program interface in the Java language used to standardize how client programs access the database, and provides methods such as querying and updating data in t ...

preface Recently, I began to bite the openGauss compatible package. I'll practice with a simpler one first. UTL_ The url package has only two functions, "ESCAPE" and "unscape", which are actually two functions of URLENCODE and URLDECODE used in other development languages. They are mainly used to process some specific char ...

Happy New Year! The first blog in 2022 is mainly because I don't like summarizing, so I need to read more and summarize more. Then it's today's review! 1.vector vector<int>a; a.push_back(); a.pop_back(); a.insert(a.begin() + i, k);//Insert from position i for (vector<int>::iterator i = a.begin(); i != a.end(); i++) { cout ...

prepare 1. Confirm that binlog is enabled show variables like 'log_%'; After execution, log in the red box below_ Bin on means binlog is on 2. Prepare database tables and data for operation CREATE TABLE `study`.`tb_class` ( `id` int(11) NOT NULL, `name` varchar(255) DEFAULT NULL, `score` int(255) DEFAULT NULL, `grade` varcha ...