jdbc starts from scratch

One. Remember to build the connection foundation before getting the database 1. driver 2. connection 3. statement 4. resultSet //1 Class.forName(ConfigUtil.getValue("driver")); //2 Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/resource_integrate","root","root");//The three paramete ...

Posted by texmansru47 on Thu, 02 Apr 2020 11:59:01 +0200

The 100th blog post of Xiao Liu

Achieve [100 blog achievements] With the teacher's video, the interface has been written today, mainly including the user details page, which is called "riend" and "detail". posts friend circle article interface: // All under the user posts Interface router.get('/:id/post', (req, res) => { connect.query( 'se ...

Posted by crunchyfroggie on Thu, 02 Apr 2020 07:12:41 +0200

Phoenix + HBase, let you operate HBase like MySQL

Operation of Phoenix associated HBase (three cases) Situation 1: Hbase already has existing tables. You can create corresponding views in Phoenix. Views can only be queried, not added, deleted or modified Table has been created and data exists in hbase, table name: phoenix Create the corresponding view in phoenix create view "phoenix"( pk ...

Posted by estero2002 on Wed, 01 Apr 2020 21:47:10 +0200

MySQL common operations (2) user management, common statements, database backup and recovery

1. mysql user management In daily use, it is necessary to limit the permissions of personnel, so it is necessary to manage users. ##Create users and authorize Specify login IP [root@host ~]# mysql -uroot -p Enter password: Welcome to the MySQL monitor. mysql> grant all on *.* to 'user1'@'127.0.0.1' identified by '123456'; #Create user1 us ...

Posted by pucker22 on Wed, 01 Apr 2020 20:18:42 +0200

vue+node+mySql to separate front and back end

Environment building Install node first: http://nodejs.cn/download/ Download and install it directly! The new version does not need to manually configure the environment. After installation, open cmd and input node-v and npm-v to check whether the installation is successful. The second step is to install vue: T ...

Posted by Concat on Wed, 01 Apr 2020 13:05:01 +0200

New tablespaces and corresponding users of Oracle database based on database technology

New tablespaces and corresponding users in Oracle Database Create tablespace and temporary tablespace data files Create a tablespace data file SQL> CREATE TABLESPACE rec_news LOGGING DATAFILE '/home/oracle/OracleDB/user/rec_news/rec_news.dbf' SIZE 100M AUTOEXTEND ON NEXT 100M MAXSIZE 5120M EXTENT MANAGEMENT LOCAL; Ta ...

Posted by SpasePeepole on Wed, 01 Apr 2020 03:05:27 +0200

MySQL parallel replication records updated from the database do not exist, but exist

Parallel replication records updated from the library do not exist, but exist background The semi synchronous slave database SQL thread with parallel replication enabled reports 1032 errors, while the asynchronous slave database does not report any errors. This happens occasionally Analysis Version mysql 5.7.16 mysql> show variables like '%s ...

Posted by johnkelly on Tue, 31 Mar 2020 08:41:14 +0200

[MyBatis] learning summary 6: dynamic SQL

Introduction Dynamic SQL: dynamic SQL. In this section, we will learn from the official documents of MyBatis. Description The official description is as follows: One of the most powerful features of MyBatis has always been its Dynamic SQL capabilities. If you have any experience with JDBC or any similar framework, you understand how painful it ...

Posted by Squiggles on Mon, 30 Mar 2020 23:25:00 +0200

MySQL data definition language (DDL)

SQL consists of the following four parts: 1 data definition language (DDL): DROP, CREATE, ALTER and other statements. 2 data operation language (DML): INSERT, UPDATE and DELETE statements. 3 data query language (DQL): SELECT statement. 4 data control language (DCL): GRANT, REVOKE, COMMIT, ROLLBACK and other statements. DDL(Dat ...

Posted by zaneosak on Mon, 23 Mar 2020 16:38:48 +0100

MySQL field constraint and multi table query

The field constraint of mysql is inevitable in the future. There are four main contents as follows: the primary key constraint is used for uniqueness and cannot be empty; the non empty constraint cannot be empty and can be repeated; the unique constraint can be empty but must be unique; the foreign key constraint is to make a certain associatio ...

Posted by Candrew on Mon, 23 Mar 2020 12:04:35 +0100