id int primary key, num varchar(18), CONSTRAINT p_id_fk FOREIGN KEY(id) REFERENCES person(id) ); 2.7 级联操作 级联修改: ON UPDATE CASCADE 级联删除: ON DELETE CASCADE -- 声明一个外键约束 CONSTRAINT emlyee_dept_fk FOREIGN KEY(deptId) REFERENCES dept(id) ON UPDATE CASCADE ON DELETE CASCAD...
CREATE TABLE major( id INT PRIMARY KEY, major_name VARCHAR(20) ); DROP TABLE IF EXISTS myStuinfo; CREATE TABLE myStuinfo( id INT PRIMARY KEY AUTO_INCREMENT, cname VARCHAR(20), majorId INT, CONSTRAINT majorid_to_major FOREIGN KEY (majorid) REFERENCES major(id) ON DELETE CASCADE ); 1. ...
(col17_w0_33) ON DELETE CASCADE ON UPDATE CASCADE" ], "usesDeclarativeSchemaChanger": true } } schema_change_external_test.go:129: Error Trace: pkg/ccl/testccl/workload/schemachange/schemachange_test_test/pkg/ccl/testccl/workload/schemachange/schema_change_external_test.go:129 Error: ...
drop_swap:禁用外键约束(FOREIGN_KEY_CHECKS=0),在进行重命名新父表之前删除原父表,这与常规转换旧表与新表的方式不同,这个RENAME操作是原子性的并且对应用客户端无感知。 这种方式更快速并且不会阻塞,但是也有隐患:1.删除原父表以及重命名新表这段时间很短,如果这段时间更改子表有可能会报错;2.如果重命名新...
如果'--alter'选项中包含DROPPRIMARYKEY删除主键的操作,除非指定选项'--dry-run',否则工具将退出。变更表的主键是十分危险的,工具变更时建立的触发器,尤其是DELETE触发器,是基于主键的,在做主键变更前先添加选项'--dry-run'和'--print'验证触发器是可用的。--[no]check-replication-filters默认值:yes ...
$table->foreign('user_id')->references('id')->on('users')->onDelete('cascade'); This line adds a new foreign key constraint on theuser_idcolumn with theonDelete('cascade')behavior. Down Method:Thedownmethod is used to reverse the changes made in theupmethod. It drops the new foreig...
CascadeDeleteTiming Gets or sets a value indicating when a dependent/child entity will have its state set to Deleted once its parent/principal entity has been marked as Deleted. The default value isImmediate. Context Gets the context this change tracker belongs to. DebugView Expand this propert...
CascadeDeleteTiming Gets or sets a value indicating when a dependent/child entity will have its state set to Deleted once its parent/principal entity has been marked as Deleted. The default value isImmediate. Context Gets the context this change tracker belongs to. DebugView Expand this propert...
// Enable foreign key constraint to make sure that deletes cascade tx := db.Exec("PRAGMA foreign_keys = ON") if tx.Error != nil { return nil, tx.Error } @@ -43,9 +36,6 @@ PRAGMA journal_mode = WAL; sqlDB.SetConnMaxLifetime(5 * time.Minute) sqlDB.SetConnMaxIdleTime(3 *...
key of foo that is 'Not Null' and has both 'Restrict' for 'On Delete' and 'On Cascade' (and then apply changes and close the create table dialog) 3. Reopen the Edit Table window for the table 'bar' 4. Change 'On Delete' to 'Set Null' 5. Click 'Apply Changes' 6. Click '...