`tid` INT(10) DEFAULT NULL, PRIMARY KEY (`id`), KEY `fktid` (`tid`), CONSTRAINT `fktid` FOREIGN KEY (`tid`) REFERENCES `teacher` (`id`) ) ENGINE=INNODB DEFAULT CHARSET=utf8 INSERT INTO `student` (`id`, `name`, `tid`) VALUES ('1', '小明', '1'); INSERT INTO `student`...
CONSTRAINT emlyee_dept_fk FOREIGN KEY(deptId) REFERENCES dept(id) 约束 外键名称 外键 参照 参考表(参考字段) 外键 多表的设计 一对多:(非常多) CREATE TABLE department( id int primary key, name varchar(100), floor int ); CREATE TABLE employee( id int primary key, name varchar(100), salary ...
SQL CREATE VIEW SQL Index SQL CREATE INDEX SQL DROP TABLE SQL TRUNCATE TABLE SQL USE SQL CREATE DATABASE SQL DROP DATABASE SQL GRANT SQL REVOKE SQL CONSTRAINT NOT NULL Constraint DEFAULT Constraint UNIQUE Constraint CHECK Constraint PRIMARY KEY FOREIGN KEY SQL ALTER TABLE Add Column Change Column...
SQL View SQL CREATE VIEW SQL Index SQL CREATE INDEX SQL DROP TABLE SQL TRUNCATE TABLE SQL USE SQL CREATE DATABASE SQL DROP DATABASE SQL GRANT SQL REVOKE SQL CONSTRAINT NOT NULL Constraint DEFAULT Constraint UNIQUE Constraint CHECK Constraint PRIMARY KEY FOREIGN KEY SQL ALTER TABLE Add Column Chan...
How To Auto Increment Alphanumeric Primary Key In sql server 2008 How to auto logout a user from ASP.Net site after s/he is idle for more than X minutes ? How to autoclick on the URL without user's interactivity how to automatically close browser window how to avoid editing data by ...
Integrity Constraints in Create Table not null primary key (A1, ..., An ) foreign key (Am, ..., An ) references r Example: create tablestudent ( ID varchar(5), name varchar(20) not null, dept_name varchar(20), tot_cred numeric(3,0), ...
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From the manual: "IGNORE is a MySQL extension to standard SQL. It controls how ALTER TABLE works if there are duplicates on unique keys in the new table or if warnings occur when strict mode is enabled. If IGNORE is not specified, the copy is aborted and rolled back if duplicate-key ...
As I had been spending the day carefully planning out a manual data layout for my product in a more tradition key value store I immediately "got it" and I was like "OMG I AM SOLD: THESE PEOPLE THOUGHT OF EVERYTHING". And then I put it on my todo list to figure out how to use ...
from sqlmodel import Field, Relationship, Session, SQLModel, create_engine class HeroTeamLink(SQLModel, table=True): team_id: int | None = Field(default=None, foreign_key="team.id", primary_key=True) hero_id: int | None = Field(default=None, foreign_key="hero.id", primary_key=True...