The constraints and indexes in Mysql creation Bitmap_join_indexes _mysql

The test process is as follows:
CREATE TABLE Sales
As SELECT * from Sh.sales;

CREATE TABLE Customers

As
SELECT * from Sh.customers;
Create unique index Cust_id_un on customers (cust_id);


Create:
Bitmap Join Indexes

Create Bitmap Index Sales_cust_gender_bjix
On sales (Customers.cust_gender)
From Sales,customers
where sales.cust_id=customers.cust_id;

The error is as follows:


Line 3rd Error:
ORA-25954: The primary KEY or UNIQUE constraint for the dimension is missing
Case study: Although the uniqueness index for table customers is defined here, the index does not have a uniqueness constraint on the table customers, that is, the uniqueness index does not represent a uniqueness constraint on the table, but if the uniqueness constraint is added, the error will not occur, as shown in the following example:


Sql> ALTER TABLE Customers
2 MODIFY (cust_id CONSTRAINT customers_un unique);
The table has changed.

Sql> Create bitmap Index Sales_cust_gender_bjix

2 on sales (Customers.cust_gender)
3 from Sales,customers
4 where sales.cust_id=customers.cust_id;


The index has been created.



Conclusion:

Creating a Bji is not an error, as long as the uniqueness constraint is added.