How can I list all foreign keys referencing a given table in SQL Server?  how to check if columns in table was used as foreign key in other tables   Not sure why no one suggested but I use sp_fkeys to query foreign keys for a given table: EXEC sp_fke…

本文转自:https://stackoverflow.com/questions/483193/how-can-i-list-all-foreign-keys-referencing-a-given-table-in-sql-server EXEC sp_fkeys 'TableName' SELECT    'ALTER TABLE ['+sch.name+'].['+referencingTable.Name+'] DROP CONSTRAINT ['+foreignKey.name+']'…

Every movie needs a director and every rented movie needs to exist in the store. How do we make sure something in another table exists before inserting new data? This lesson will teach us about foreign keys and references. CREATE TABLE directors ( id…

在数据库里面使用TRUNCATE命令截断一个表的数据时,遇到如下错误 SQL >TRUNCATE TABLE ESCMOWNER.SUBX_ITEM ORA-02266: unique/primary keys in table referenced by enabled foreign keys 有时候对应的中文错误提示为:ORA-02266: 表中的唯一/主键被启用的外部关键字引用,一般出现这个错误,是因为表中的主键被其它表的外键所引用,导致删除数据时出错. 此时,你可以通过下面脚本查看一下…

关于ORA-02273错误,以前还真没有仔细留意过.昨天遇到了这个问题,遂顺便总结一番,以后遇到这类问题就可以直接用下面方案解决.如下所示,我们首先准备一下测试环境. CREATE TABLE TEST.TEST (  OWNER            VARCHAR2(30),    OBJECT_ID        NUMBER,    OBJECT_NAME      VARCHAR2(30) );   CREATE INDEX TEST.IX_TEST_N1 ON TEST.TEST(O…

https://docs.microsoft.com/en-us/sql/relational-databases/tables/create-foreign-key-relationships?view=sql-server-2017 Create a foreign key relationship in Table Designer Create a foreign key relationship in Table Designer Using SQL Server Management…

in table design view(right click table and choose design), right click on a column, and select 'relationship', then create your foreign keys, sql, stop changes that require recreating table: select tools ->options-> designer, then remove checked fro…

原文:Sql Server 2008R2版本中有关外键Foreign的使用 1. 在数据库设计的过程中往往会想让2张表进行关联而使用到Foreign从而加强2张表之间的约束(如图) 以前有个问题一直没弄明白,那就是外键列的值的情况,正常情况下表中的列的值可以是null或者满足该列所定义的类型的数据即可,但是外键是不是也一样呢? 答案显然不是的,那到底是个什么情况呢? 官方帮助文档是这样说明的“FOREIGN KEY 约束并不仅仅可以与另一表的 PRIMARY KEY 约束相链接,它还可以定义为引…

down voteaccepted For a Table: SELECT TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME, REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE REFERENCED_TABLE_SCHEMA = '<database>' AND REFERENCED_TABLE_NAME = '<table&g…

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在SQL Server中,表之间存在引用关系,引用关系通过创建外键约束(Foreign Key Constraint)实现.如果一个Table中的column被其他Table引用,那么该表是参考表,或引用表(Referenced Table),该Column是其他表的外键列,也叫参考列,引用列(Referenced Column),对引用列执行Update 或 Delete 操作会受到很多限制.在对引用列进行Update 和 Delete之前,必须禁用外键约束. 1,查看FK的信息,使用 sys…

ntroduction to MySQL foreign key A foreign key is a field in a table that matches another field of another table. A foreign key places constraints on data in the related tables, which enables MySQL to maintain referential integrity. Let’s take a look…

Oracle primary,unique,foreign 区别 转:http://www.cnblogs.com/henw/archive/2012/08/15/2639510.html NOT NULL : 用于控制字段的内容一定不能为空(NULL). UNIQUE : 控件字段内容不能重复,一个表允许有多个 Unique 约束. PRIMARY KEY: 也是用于控件字段内容不能重复,但它在一个表只允许出现一个. FOREIGN KEY: FOREIGN KEY 约束用于预防破坏表之间连接…

原文链接:http://www.c-sharpcorner.com/UploadFile/3d39b4/relationship-in-entity-framework-using-code-first-approach-w/ In this article, you will learn about relationships in Entity Framework using the Code First Approach with Fluent API. 在这篇文章中,你将会学习到使用EF…

背景: MySQL 大字段的DDL操作:加减字段.索引.修改字段属性等,在5.1之前都是非常耗时耗力的,特别是会对MySQL服务产生影响.在5.1之后随着Plugin Innodb的出现在线加索引的提高了很多,但是还会影响(时间缩短了),主要是出现了MDL锁.不过5.6可以避免上面的情况,但目前大部分在用的版本都是5.6之前的,所以DDL操作一直是运维人员“头疼"的事.那如何在不锁表的情况下安全快速地更新表结构?现在来说明下percona-toolkit 的pt-online-schema-ch…

Summary: this tutorial shows you how to use MySQL handler to handle exceptions or errors encountered in stored procedures. When an error occurs inside a stored procedure, it is important to handle it appropriately, such as continuing or exiting the c…

问题描述:当父表有子表的外键约束时,无法直接truncate父表.报ORA-02266: unique/primary keys in table referenced by enabled foreign keys.这里使用另一种办法来解决这个问题:先把外键失效,truncate表之后再把外键生效.SQL> truncate table machine_room;truncate table machine_room *ERROR at line 1:ORA-02266: unique/pri…

1, primary key 可以带空格 做为下表 但field就不行 2, dev_node 仅为下标 'primary key' => array('nid'),    'foreign keys' => array(      'dnv_node' => array(        'table' => 'node',        'columns' => array('nid' => 'nid'),      ),    ),…

/** The handler class is the interface for dynamically loadable storage engines. Do not add ifdefs and take care when adding or changing virtual functions to avoid vtable confusion */ class handler :public Sql_alloc { public: typedef ulonglong Table_…

1. View the Exhibit andexamine the structure of the SALES, CUSTOMERS, PRODUCTS, and TIMES tables. The PROD_ID column isthe foreign key in the SALES table, which references the PRODUCTS table. Similarly, the CUST_IDand TIME_ID columns are also foreign…

This tutorial shows you how to use MySQL handler to handle exceptions or errors encountered in stored procedures. When an error occurs inside a stored procedure, it is important to handle it appropriately, such as continuing or exiting the current co…

原文地址 http://www.cnblogs.com/zhycyq/articles/2636748.html 50种方法优化SQL Server数据库查询 查询速度慢的原因很多,常见如下几种: 1.没有索引或者没有用到索引(这是查询慢最常见的问题,是程序设计的缺陷) 2.I/O吞吐量小,形成了瓶颈效应. 3.没有创建计算列导致查询不优化. 4.内存不足 5.网络速度慢 6.查询出的数据量过大(可以采用多次查询,其他的方法降低数据量) 7.锁或者死锁(这也是查询慢最常见的问题,是程序设计的缺陷…

存储过程编写经验和优化措施 一.适合读者对象:数据库开发程序员,数据库的数据量很多,涉及到对SP(存储过程)的优化的项目开发人员,对数据库有浓厚兴趣的人. 二.介绍:在数据库的开发过程中,经常会遇到复杂的业务逻辑和对数据库的操作,这个时候就会用SP来封装数据库操作.如果项目的SP较多,书写 又没有一定的规范,将会影响以后的系统维护困难和大SP逻辑的难以理解,另外如果数据库的数据量大或者项目对SP 的性能要求很,就会遇到优化的问题,否则速度有可能很慢,经过亲身经验,一个经过优化过的SP要比一个性能…

1. View the Exhibit and examine the structure of the SALES, CUSTOMERS, PRODUCTS, and TIMES tables. The PROD_ID column is the foreign key in the SALES table, which references the PRODUCTS table. Similarly, the CUST_ID and TIME_ID columns are also fore…

===================== Model field reference ===================== .. module:: django.db.models.fields :synopsis: Built-in field types. .. currentmodule:: django.db.models This document contains all the API references of :class:Field including the fie…

背景: MySQL 大字段的DDL操作:加减字段.索引.修改字段属性等,在5.1之前都是非常耗时耗力的,特别是会对MySQL服务产生影响.在5.1之后随着Plugin Innodb的出现在线加索引的提高了很多,但是还会影响(时间缩短了),主要是出现了MDL锁.不过5.6可以避免上面的情况,但目前大部分在用的版本都是5.6之前的,所以DDL操作一直是运维人员“头疼"的事.那如何在不锁表的情况下安全快速地更新表结构?现在来说明下percona-toolkit 的pt-online-schema-ch…

pt-online-schema-change - ALTER tables without locking them. pt-online-schema-change alters a table's structure without blocking reads or writes. Specify the database and table in the DSN. Do not use this tool before reading its documentation and che…

常用GHOST模板 ##================================================## mysql_ip="127.0.0.1" mysql_port= ghost_user="root" ghost_password="123.com" ghost_database="test1" ghost_table="tb002" ghost_command="ADD…

目录[-] A Fast, Simple, Typed ORM for .NET Download 8 flavours of OrmLite is on NuGet: Docs and Downloads for older v3 BSD releases Copying Contributing Examples Querying with SELECT Convenient common usage data access patterns INSERT, UPDATE and DELET…

Complete list of Microsoft SQL Server trace flags (585 trace flags) REMEMBER: Be extremely careful with trace flags, test in your test environment first. And consult professionals first if you are the slightest uncertain about the effects of your cha…