unique-constraint

can anybody help with me with this? id | Name -------- 1 | aaa 2 | bbb 3 | aaa >alter table arc add CONSTRAINT uk_arc UNIQUE (NAME) novalidate error :ora-02299: cannot validate( .uk_arc ) - duplicate keys found I am using novalidate to ignore the old duplicate and start to validate all over again. If I get you correctly, you expect Oracle to ignore old duplicate values and allow new values only when they satisfy the constraint. The error is returned because when you add a UNIQUE constraint, Oracle creates unique index on the column to check the values, but your table already have duplicate

I'm trying to create a constraint on the OE.PRODUCT_INFORMATION table which is delivered with Oracle 11g R2. The constraint should make the PRODUCT_NAME unique. I've tried it with the following statement: ALTER TABLE PRODUCT_INFORMATION ADD CONSTRAINT PRINF_NAME_UNIQUE UNIQUE (PRODUCT_NAME); The problem is, that in the OE.PRODUCT_INFORMATION there are already product names which currently exist more than twice. Executing the code above throws the following error: an alter table validating constraint failed because the table has duplicate key values. Is there a possibility that a new created

I have a few non-unique constraints that I want to alter into unique constraints ( business rules have changed since the data model was made ). Is there any way to do it with out dropping and recreating as a unique constraint? I was thinking there would be an option in the alter constraint command, but I have not found anything. Thanks!! You can't modify a constraint in the way you wish you can only drop and recreate it. If you want to do this with no downtime then look into the DBMS_REDEFINITION package. You cannot convert a non-unique index into a unique index. (It's difficult to say what

If I have the following element spec in XSD I can add the <xs:unique> constraint as a child of <xs:element name="Parent"> but I can't get it to work as a child of <xs:element name="Child"> : <xs:element name="Parent"> <xs:complexType> <xs:element name="Child" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:attribute name="Key" type="xs:string" use="required" /> </xs:complexType> <!-- Option A: insert unique constraint here with selector . --> </xs:element> </xs:complexType> <!-- Option B: insert unique constraint here with selector ./Child --> </xs:element> This is the unique

MS SQL Server does not ignore the null value and considers it as violation for the UNIQUE KEY constraint but what I know is that the UNIQUE KEY differ from the primary key where it accepts the null value. Violation of UNIQUE KEY constraint 'AK_UserName'. Cannot insert duplicate key in object 'dbo.users'. The duplicate key value is (<NULL>). The statement has been terminated. Can anyone help me to solve this problem? you can create a unique index that ignores null values like this CREATE UNIQUE NONCLUSTERED INDEX idx_col1 ON dbo.MyTable(col1) WHERE col1 IS NOT NULL; 来源： https://stackoverflow

I'm writing a very simple blog engine for own use (since every blog engine I encountered is too complex). I want to be able to uniquely identify each post by its URL which is something like /2009/03/05/my-blog-post-slug . To accomplish it in the data tier, I want to create a compound unique constraint on (Date, Slug) where Date is only the date part (ignoring the time of day) of the composition date. I have a few ideas myself (like another column, probably calculated, to hold only the date part) but I came to SO to know what's the best practice to solve this problem. I doubt SQL Server version