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[Reprint] The use of database foreign keysThe role of foreign keys:Maintain data consistency, integrity, the primary purpose is to control the data stored in the Foreign key table. Make two tables associative, and foreign keys can only refer to the

Http://www.cnblogs.com/zhouruifu/archive/2012/04/18/2454088.htmlI have always taken it for granted that using guid as the primary key is no big deal. Isn't it 12 more bits than Int? And now it's all in the SQL Server 2008,201 2 era. Isn't it a

the role of foreign keys: Maintain data consistency, integrity, the primary purpose is to control the data stored in the Foreign key table. Causes two tables to be associated, and the foreign key can only refer to the values of the columns in the

Http://www.grammar.cl/english/both-either-neither.htmBoth, either, neither Summary ChartWe Use the both, either and neither to refer to the people or things.BOTHBoth = the other; That one and the other one; This one and that oneBoth can used as a

The role of foreign keys:Maintain data consistency, integrity, the primary purpose is to control the data stored in the Foreign key table. Make two tables associative, and foreign keys can only refer to the values of columns in the outside!For

The click event of usercontrol is valid for both the left and right mouse keys. How does one make it as sensitive as the left mouse button control? The program section in this article has been improved through repeated scrutiny. For details, see

primary key foreign keys and indexes(This article is transferred from http://www.cnblogs.com/longyi1234/archive/2010/03/24/1693738.html) First, what is primary key, foreign key: a record in a relational database has several attributes, if one of

First, what is primary key, foreign key: A record in a relational database has several properties, and if one of the attribute groups (note the group) uniquely identifies a record, the attribute group can be a primary keyLike whatStudent form

MAC keyboard shortcutsYou can press the key combination to perform actions that typically require a mouse, trackpad, or other input device to complete.To use a keyboard shortcut, press and hold one or more modifier keys while pressing the last key

First, what is the primary key, foreign key:There are several attributes in a record in a relational database, which can be a primary key if one of the attribute groups (note is a group) uniquely identifies a record.Like whatStudent Table (School