You can’t truncate the table if there is any foreign key referencing it, including disabled constraints. You either need to drop the foreign key constraints or use the DELETE command.
Normally you would do that with CHECK constraint: foo_test VARCHAR(50) NOT NULL CHECK (foo_test <> ”) Prior to Version 8.0 MySQL had limited support for constraints. From MySQL Reference Manual: The CHECK clause is parsed but ignored by all storage engines. If you must stick to an old version use triggers as a workaround, as … Read more
Taken from RFC 5280, section 4.2.1.9: A pathLenConstraint of zero indicates that no non-self-issued intermediate CA certificates may follow in a valid certification path. Where it appears, the pathLenConstraint field MUST be greater than or equal to zero. Where pathLenConstraint does not appear, no limit is imposed. I.e. a pathLenConstraintof 0 does still allow the … Read more
EDIT Note that in iOS 9 this technique will become unnecessary, because a UIStackView will perform distribution automatically. I’ll add another answer explaining how that works. How to Perform Even Distribution Using Autolayout The simplest way to do this in Interface Builder alone (rather than constructing constraints in code) is to use “spacer” views: Position … Read more
No, sorry. SQL Server does not allow deferred contraints in a transaction. It was present in SQL Server 6.5, but removed in SQL Server 2000: SET DISABLE_DEF_CNST_CHK ON Each individual statement must be consistent etc, regardless of whether it is in a transaction Some RDBMS do allow this (e.g. Oracle, Postgres, Interbase) Connect There is … Read more
CHECK constraints cannot currently reference other tables. The manual: Currently, CHECK expressions cannot contain subqueries nor refer to variables other than columns of the current row. One way is to use a trigger like demonstrated by @Wolph. A clean solution without triggers: add redundant columns and include them in FOREIGN KEY constraints, which are the … Read more
you can use a CHECK constraint ALTER TABLE <table> ADD CONSTRAINT chk_val CHECK (col in (‘yes’,’no’,’maybe’)) MSDN link
You can use this code to do it automatically: DECLARE @tableName VARCHAR(MAX) = ‘<MYTABLENAME>’ DECLARE @columnName VARCHAR(MAX) = ‘<MYCOLUMNAME>’ DECLARE @ConstraintName nvarchar(200) SELECT @ConstraintName = Name FROM SYS.DEFAULT_CONSTRAINTS WHERE PARENT_OBJECT_ID = OBJECT_ID(@tableName) AND PARENT_COLUMN_ID = ( SELECT column_id FROM sys.columns WHERE NAME = @columnName AND object_id = OBJECT_ID(@tableName)) IF @ConstraintName IS NOT NULL EXEC(‘ALTER TABLE … Read more
Per previous comments, it should be a problem. That said, there is a command that may be what you’re looking to – it’ll set the constraints to deferred so they’re checked on COMMIT, not on every delete. If you’re doing just one big DELETE of all the rows, it won’t make a difference, but if … Read more