Jira issue originally created by user @doctrinebot:
This issue is created automatically through a Github pull request on behalf of deeky666:
SQL Anywhere seems to distinguish between unique indexes and unique constraints. Unique constraints do not allow NULL values while unique indexes do.
A UNIQUE constraint is not the same as a unique index. Columns of a unique index are allowed to be NULL, while columns in a UNIQUE constraint are not. Also, a foreign key can reference either a primary key or a UNIQUE constraint, but cannot reference a unique index since a unique index can include multiple instances of NULL.
The current implementation create unique constraints instead of unique indexes during CREATE TABLE statements which causes ORM to fail as all nullable columns in a unique constraint silently get converted to NOT NULL.
This PR replace unique constraints by unique indexes in CREATE TABLE.
Comment created by @doctrinebot:
A related Github Pull-Request [GH-507] was closed:
Issue was closed with resolution "Fixed"