我与动物更新多对多表SQL
CREATE TABLE Animals
(
AnimalId int NOT NULL,
Color int NOT NULL,
Breed int NOT NULL,
Genre int NOT NULL,
);
和表格一模一样的表,但一切都是可选的(除键)
CREATE TABLE Expenses
(
ExpenseId int NOT NULL,
Color int,
Breed int,
Genre int,
);
最后一个不少许多表:
CREATE TABLE AnimalsExpenses
(
ExpenseId int NOT NULL FOREIGN KEY REFERENCES Expenses(ExpenseId),
AnimalId int NOT NULL FOREIGN KEY REFERENCES Animals(AnimalId),
);
记录(A,E)应该在桌子上AnimalsExpenses如果
((SELECT Color FROM Animals WHERE AnimalId = a) = (SELECT Color FROM Expenses WHERE ExpenseId = e)
OR (NULL) = (SELECT Color FROM Expenses WHERE ExpenseId = e))
AND
((SELECT Breed FROM Animals WHERE AnimalId = a) = (SELECT Breed FROM Expenses WHERE ExpenseId = e)
OR (NULL) = (SELECT Breed FROM Expenses WHERE ExpenseId = e))
AND
((SELECT Genre FROM Animals WHERE AnimalId = a) = (SELECT Genre FROM Expenses WHERE ExpenseId = e)
OR (NULL) = (SELECT Genre FROM Expenses WHERE ExpenseId = e))
...它将如何成为更新AnimalsExpenses的查询?那就是:它会删除不应该是在纳米表中的记录,并补充说,需要在那里的那些
例子:
------ Animals -------------------
AnimalId Color Breed Genre
----------------------------------
1 1 1 1
2 1 1 2
3 1 2 2
----- Expenses -------------------
ExpenseId Color Breed Genre
----------------------------------
1 NULL NULL NULL (applies to every animal)
2 NULL 2 NULL (applies to animals of breed 2)
3 1 2 2 (applies exactly to animal 3)
----- AnimalsExpenses -------------------------------------------
AnimalId ExpenseId Is it ok?
-----------------------------------------------------------------
1 1 yes, because "expense 1" applies to all
2 1 yes, because "expense 1" applies to all
3 1 yes, because "expense 1" applies to all
1 2 no, breed doesnt match
2 2 no, breed doesnt match
3 2 yes, because "expense 2" matches breed with "animal 3"
1 3 no, breed and genre doesnt match
2 3 no, breed doesnt match
3 3 yes, everything matches
您正在使用哪个SQL供应商?我可能会在应用层而不是数据库中执行此操作。 –
SQL Server。我正在使用LINQ/Entity Framework进行此更新,但速度太慢 – sports
您能否包含一些示例数据并告诉我们允许和禁止的条目是什么样子? –