Id_P int, PRIMARY KEY (Id_O),CONSTRAINT fk_PerOrders FOREIGN KEY (Id_P) REFERENCES Persons(Id_P)) SQL FOREIGN KEY Constraint on ALTER TABLE 如果在 "Orders" 表已存在的情况下为 "Id_P" 列创建 FOREIGN KEY 约束,请使用下面的 SQL: MySQL / SQL Server / Oracle / MS Access: ALTER TABLE ...
MySQL Alter Table Statement Exercises: Write a SQL statement to add a foreign key on job_id column of job_history table referencing to the primary key job_id of jobs table.
对于MySQL，第一种语法是错误的。第二种是MySQL的正确语法。请参阅此链接：https://www.w3schools.com...
MySQL FOREIGN KEY ConstraintThe FOREIGN KEY constraint is used to prevent actions that would destroy links between tables.A FOREIGN KEY is a field (or collection of fields) in one table, that refers to the PRIMARY KEY in another table.
To create a FOREIGN KEY constraint on the "P_Id" column when the "Orders" table is already created, use the following SQL:MySQL / SQL Server / Oracle / MS Access:ALTER TABLE Orders ADD FOREIGN KEY (P_Id) REFERENCES Persons(P_Id)...
20.Write a MySQL query to create a table employees including columns employee_id, first_name, last_name, job_id, salary and make sure that, the employee_id column does not contain any duplicate value at the time of insertion, and the foreign key column job_id, referenced by the column ...
“cannot delete or update a parent row: a foreign key”错误详解 1. 错误含义 “cannot delete or update a parent row: a foreign key”错误通常发生在数据库操作中,特别是在尝试删除或更新一个作为外键引用的父表记录时。这个错误表明,由于存在外键约束,你无法删除或更新父表中的相关记录,因为这些记录正在...
Cannot add or update a child row: a foreign key constraint fails (`kims`.`questi on`, CONSTRAINT `fk_question_su bject` FOREIGN KEY (`sub_code`) REFERENCES `subject` (`subject_code` ) ON DELETE NO ACTION ON UPDATE NO ACTION) Here is my code and data base structure. C...
Add a foreign key to the CSV file id;count;name;purse_id 1;37454;Directives application Home Loan Account;1 2;15601;Computer Practical Fresh Pants;2 3;60111;alarm;3 4;2058;Producer;4 run the application Related issues NO Suggest a Fix ...
0 mysql> ALTER TABLE `UserRoleCompanie` ADD CONSTRAINT companie FOREIGN KEY (`companieId`) REFERENCES `Companie`(`id`); ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails (`nacho@prod`.`#sql-1_83f`, CONSTRAINT `companie` FOREIGN KEY (`companieI...