id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,pull_request,body,repo,type,active_lock_reason,performed_via_github_app,reactions,draft,state_reason
1754174496,I_kwDOCGYnMM5ojpQg,558,Ability to define unique columns when creating a table,1910303,open,0,,,0,2023-06-13T06:56:19Z,2023-06-13T06:56:19Z,,NONE,,"When creating a new table, it would be good to have an option to set unique columns similar to how not_null is set.

```python
from sqlite_utils import Database

columns = {""mRID"": str, ""name"": str}
db = Database(""example.db"")
db[""ExampleTable""].create(columns, pk=""mRID"", not_null=[""mRID""], if_not_exists=True)
db[""ExampleTable""].create_index([""mRID""], unique=True, if_not_exists=True)
```

So something like this would add the UNIQUE flag to the table definition. 

```python
db[""ExampleTable""].create(columns, pk=""mRID"", not_null=[""mRID""], unique=[""mRID""], if_not_exists=True)
```

```sql
CREATE TABLE ExampleTable (
    mRID TEXT PRIMARY KEY
              NOT NULL
              UNIQUE,
    name TEXT
);
```",140912432,issue,,,"{""url"": ""https://api.github.com/repos/simonw/sqlite-utils/issues/558/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,