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1·So, it violates unique constraint across the collection.

所以，它违背了独特的约束集合。

2·Can't remove unique constraint since it's the primary key of a table.

唯一约束是表的主键，因此不能移除。

3·The unique constraint is created in the database when you save the table.

当保存表时，将在数据库中创建该唯一约束。

4·Tables must have the same primary key, unique index, or unique constraint.

表必须具有相同的主键、唯一索引或唯一约束。

5·A Unique constraint guarantees that there are no duplicates in a specific column and allows you to define a primary key.

唯一约束可以保证在特定的列中没有重复值并允许您定义一个主键。

6·You can attach multiple unique constraints to a table, whereas you can attach only one primary key constraint to a table.

可将多个唯一约束附加到表，但是只能将一个主键约束附加到表。

7·This clause is not allowed if the column is specified in the primary key, or in a unique constraint of the table (SQLSTATE 42831).

如果表的主键或惟一性约束中指定了这个列，那么不允许使用这个子句(SQLSTATE 42831)。

8·Create a unique constraint to ensure no duplicate values are entered in specific columns that do not participate in a primary key.

创建唯一约束可确保在不参与主键的特定列中不输入重复值。

9·When you select the type, the appropriate dialog box opens (Unique constraint or Foreign Key constraint) to help you create the constraint.

显示适当的对话框(唯一约束或外键约束)，从而允许您更改约束的属性。

10·When you attach a unique constraint to a column allowing null values, you ensure that at most one row will have a null value in the constrained column.

当将唯一约束附加到允许空值的列时，请确保在约束的列中最多有一行包含空值。