To access this dialog box, open the table definition for the table with the foreign key, right-click the table definition grid, and click Relationships. Options Selected Relationship Lists existing relationships. Select a relationship to show its properties in the grid to the right. If the list...
1. 外键 外键(foreignkey)以及参考完整性限制(referentialintegrity)可以让你制定表格中资料间的约束,然后将约束(constraint)加… www.360doc.com|基于451个网页 2. 外健 ... 一种是主键(PrimaryKey)关联, 一种是外健(ForeignKey)关联. 在主键关联的情况下, 显然必须有一个主键是根据别一个主键而 … ...
CONSTRAINT [PK_T_STUDENT] PRIMARY KEY CLUSTERED ( [ID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO EXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=...
Foreign key constraints (also known as referential constraints or referential integrity constraints) enable definition of required relationships between and within tables.
Then create the child table using the new definition shown here:CREATE TABLE child ( par_id INT NULL, child_id INT NOT NULL, UNIQUE (par_id, child_id), FOREIGN KEY (par_id) REFERENCES parent (par_id) ON DELETE SET NULL ON UPDATE SET NULL ) ENGINE = INNODB;...
You're looking to parse a database schema and data to determine which tables are relevant or should be related to each other, without any strict definition of the relationship. In effect, you're trying to infer a relationship. I see two ways that you can infer such a relationship. First...
SqlServer 表生成Creation sql, Foreign Key Definition, Sql,USE[test]GO/***Object:Table[dbo].[T_Student]ScriptDate:10/12/201019:28:09***//***
To add a foreign key to an existing table, you use the ALTER TABLE statement with the foreign key definition syntax above: ALTER table_nameADD CONSTRAINT constraint_name FOREIGN KEY foreign_key_name(columns) REFERENCES parent_table(columns) ON DELETE action ON UPDATE action; ...
I used MySQL Workbench 6.3 for creating my data model (awesome tool). I noticed that when the column order defined in the foreign key constraint definition does not fit the table column sequence, this error is also generated. It took me about four hours of trying everything else but ...
also permits fast access to data when the primary key is used in queries. If a primary key constraint is defined on more than one column, values can be duplicated within one column, but each combination of values from all the columns in the primary key constraint definition must be unique....