I know that in MySQL, UNIQUE constraits don\'t treat NULL values as equal.So if I have a unique constraint on ColumnX, then two separate rows 开发者_开发知识库can have values of NULL for ColumnX and t
I had a constraint in a table CREATE TABLE \"USERSAPPLICATIONS\" ( \"USERID\" NUMBER NOT NULL , \"APPLICATIONNAME\" VARCHAR2 (30) NOT NULL ,
I\'m looking for a implementation of java.util.Queue or something in the Google collection who behave like a Queue, but also ensure that each element of the queue is unique. (all further inse开发者_运
I am using SQL Server 2000, I have a situation where I am copying data over from one table to another, the destination data table requires ea开发者_如何学运维ch Name row to be unique. Here is a quick
We\'re getting a ORA-00001 (unique constraint violated) in a batch job. However, the error occurs when a COMMIT is issued, not at the time the offending record is inserted.
I\'ve got a questi开发者_JAVA技巧on to which I\'ve had opposing pieces of advice, would appreciate additional views.
Is it possible to have a varchar col开发者_StackOverflow中文版umn as a primary key with values like \'a \' and \'a\', is gives always this error \"Violation of PRIMARY KEY constraint\" in MS SQL Serve
I am using an oracle table and have cr开发者_运维知识库eated a unique constraint over four columns. Can these columns within the constraint have NULL in them?you can have NULLs in your columns unless
I have to add a unique constraint to an existing table. This is fine except that the table has millions of rows already, and many of the rows violate the unique constraint I need to add.
I have a simple table in my SQL Server database. This table contains two columns: ID int, Name nvarchar(50). The ID column is the primary key for my table.
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