Question : I am trying to put the following entity-model into practice: We have a list of Payments, each Payment […]
Tag: constraint
Adding constraint on data
Question : I created a table called customer, which consists of one attribute called email. Then I would like to […]
Constrains relationship
Question : I have the following design. Each user has it’s own contacts, it’s own hosts and assign those to […]
SQL Azure: Drop Constraint and Index
Question : This may be a stupid question, but I’m not a DBA and just wanna make sure of what […]
foreign key constraint violation issue
Question : I have identified 3 situations. A student with no enrollments. A student with enrollments but no grades. A […]
Mutually exclusive many-to-many relationships
Question : I have a table containers that can have a many-to-many relationships to several tables, let’s say those are […]
Creating a partial unique constraint for MySQL
Question : I have the same question as asked in a previous post: PostgreSQL multi-column unique constraint and NULL values. […]
How to constrain data
Question : I have 3 tables which are related and a constraint on one of them which I can enforce […]
How to add a named constraint in Oracle SQL?
Question : I have a table. I need to add a NOT NULL constraint to one of the columns. This […]
Table column references partial key of table B
Question : In my database (MS SQL Server) I use language specific texts. So I defined table Texts as follows: […]