I am using SQL Server. I have this table: CREATE TABLE Student ( ID int PRIMARY KEY, FirstName varchar(100), LastName varchar(100), Active bit; ) I want to have unique(FirstName, …
Tag: constraints
Generically identify the rowid causing a constraint conflict in SQLite
I need to identify the row that caused a constraint check to fail after an INSERT OR IGNORE statement. I need this for a tool that generates SQL statements, so I can’t tie this to a specific use case …
Postgres constraint for unique datetime range
My table has two columns: startsAt endsAt Both hold date and time. I want to make following constraint: IF both columns are NOT NULL then range between startsAt and endsAt must not overlap with other ranges (from other rows). Answer You can keep your separate timestamp columns and still use an exclusion constraint on an expression: Constructing a tsrange value
Rename a constraint in SQL Server?
Is it possible to rename a constraint in SQL Server? I don’t want to have to delete and create a new one because this constraint affects other already existing constraints and I will have to recreate/alter those. Answer You can rename using sp_rename using @objtype = ‘OBJECT’ This works on objects listed in sys.objects which includes constraints
How do I add a custom CHECK constraint on a MySQL table?
I am having trouble with this table I want to have a foreign key constraint, and that works. Then, I also want to add a constraint to the attribute status so it can only take the values ‘a’, ‘d’ and ‘u’. It is not possible for me to set the field as Enum or set. Can anyone tell me why
Postgres: Add constraint if it doesn’t already exist
Does Postgres have any way to say ALTER TABLE foo ADD CONSTRAINT bar … which will just ignore the command if the constraint already exists, so that it doesn’t raise an error? Answer This might help, although it may be a bit of a dirty hack: Then call with: Updated: As per Webmut’s answer below suggesting: That’s probably fine in
Unable to drop constraint in SQL server 2005, “Could not drop constraint. See previous errors”
I’m trying to drop a constraint on a DB table, something like: But the execution just runs and runs. If I stop it I see: Web search throws up various pages but note that the constraint is properly named and I am trying to remove it using the correct name Answer Found a way to sort this, although I don’t
Displaying the constraints in a table
Hello I am trying to display the constraints in one of my tables but for some reason I get the message no rows selected. Noted below is the table I have created. This is the code I am using to show my constraints. I am a rookie so I want to make sure I understand what is wrong. I have
SQL constraint minvalue / maxvalue?
Is there a way to set a SQL constraint for a numeric field that min value should be 1234 and max value should be 4523?
Deferrable Constraints in SQL Server
Do any versions of SQL Server support deferrable constraints (DC)? Since about version 8.0, Oracle has supported deferrable constraints – constraints that are only evaluated when you commit a …