个人学习、工作笔记

1，centos自带mariadb，需要提前卸载 # 检查是否安装了mariadb root[/root]#rpm -qa |grep -i mariadb mariadb-5.5.52-1.el7.x86_64 mariadb-server-5.5.52-1.el7.x86_64 # 卸载 root[/root]#rpm -e --nodeps mariadb-5.5.52-1.el7.x86_64 root[/root]#rpm -e --nodeps mariadb-server-5.5.52-1.e

字段和数据库关键字冲突 用反撇号（`）包住，比如database SELECT id, org_id, version, type, name, access, url, password, user, `database`, basic_auth, basic_auth_user, basic_auth_password, is_default, created, updated, with_credentials, read_only, uid ,json_data, secure_.

查询表中有哪些字段 select * from user_tab_columns where table_Name='表名' order by column_name all_tab_columns ,dba_tab_columns 查询表的注释 select table_name,table_type,comments from user_tab_comments where table_Name='表名' dba_tab_comments，all_tab_comments 查询字段注释 .

SQL创建表 CREATE TABLE IF NOT EXISTS t_user(uid integer primary key,uname varchar(20),mobile varchar(20)) CREATE TABLE `data_source` ( `id` INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL , `org_id` INTEGER NOT NULL , `version` INTEGER NOT NULL , `type` TEXT NO.