Top "Constraints" questions

How to add not null constraint to existing column in MySQL

I have table name called "Person" with following column names P_Id(int), LastName(varchar), FirstName (varchar). I forgot to …

mysql constraints

SQL Server 2005 How Create a Unique Constraint?

How do I create a unique constraint on an existing table in SQL Server 2005? I am looking for both the …

sql sql-server constraints

Unique Key constraints for multiple columns in Entity Framework

I'm using Entity Framework 5.0 Code First; public class Entity { [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)] public string EntityId { get; set;} public int …

entity-framework ef-code-first constraints multiple-columns unique-key

"Insert if not exists" statement in SQLite

I have an SQLite database. I am trying to insert values (users_id, lessoninfo_id) in table bookmarks, only if …

sqlite constraints sql-insert

What are database constraints?

What is a clear definition of database constraint? Why are constraints important for a database? What are the types of …

sql sql-server constraints rdbms

SQL Server 2008- Get table constraints

Could you help me frame a query that retrieves the constraints in all the tables, the count of constraints in …

sql sql-server sql-server-2008 constraints

How can I drop a "not null" constraint in Oracle when I don't know the name of the constraint?

I have a database which has a NOT NULL constraint on a field, and I want to remove this constraint. …

oracle plsql constraints

Creating layout constraints programmatically

I know that a lot people already asked tons of questions about this, but even with the answers I can't …

objective-c ios constraints autolayout

Foreign key constraint may cause cycles or multiple cascade paths?

I have a problem when I try to add constraints to my tables. I get the error: Introducing FOREIGN KEY …

sql sql-server constraints

Get table name by constraint name

Oracle constraint name is known. How do I find the name of the table for which this constraint is applied?

oracle constraints