issue_comments

OK, this should fix it.

create_index(..., find_unique_name=) is good. Default to false. index_foreign_keys can set it to true.

I'm leaning towards table.create_index(columns, ignore_existing_name=True) now.

Or resolve_existing_name - or skip_existing_name?

"ignore" sounds like it might not create the index if the name exists, but we want to still create the index but pick a new name.

I think I'll attempt to create the index and re-try if it fails with that error.

How to figure out if an index name is already in use? PRAGMA index_list(t) requires a table name. This does it:

sql SELECT name FROM sqlite_master WHERE type = 'index';

Looking at the method signature: https://github.com/simonw/sqlite-utils/blob/92aa5c9c5d26b0889c8c3d97c76a908d5f8af211/sqlite_utils/db.py#L1518-L1524

if_not_exists just adds a IF NOT EXISTS clause here: https://github.com/simonw/sqlite-utils/blob/92aa5c9c5d26b0889c8c3d97c76a908d5f8af211/sqlite_utils/db.py#L1549-L1561

SQLite will happily create multiple identical indexes on a table, using more disk space each time: ```pycon

import sqlite_utils db = sqlite_utils.Database("dupes.db") db["t"].insert_all({"id": i} for i in range(10000))

I'm tempted to not provide an opt-out option either: if you call table.create_index(...) without specifying an index name I think the tool should create the index for you, quietly picking an index name that works.

But... it feels wasteful to create an index that exactly duplicates an existing index. Would SQLite even let you do that or would it notice and NOT double the amount of disk space used for that index?

What would such an option be called? Some options:

• table.create_index([fk.column], force=True) - not obvious what force means here
• table.create_index([fk.column], ignore_existing_name=True) - not obvious what ignore means here
• table.create_index([fk.column], pick_unique_name=True) - bit verbose

If the user doesn't pass in an explicit name it seems like their intent is "just create me the index, I don't care what name you use" - so actually perhaps the default behaviour here should be to pick a new unique name if that name is already in use.

Then maybe there should be an option to disable that - some options there:

• table.create_index([fk.column], error_on_existing_index_name=True) - too verbose
• table.create_index([fk.column], force=False) - not clear what force means

The "index idx_generators_eia860_report_date already exists" error suggests that the problem here is actually one of an index name collision.

python table.create_index([fk.column]) This will derive a name for the index automatically from the name of the table and the name of the passed in columns: https://github.com/simonw/sqlite-utils/blob/92aa5c9c5d26b0889c8c3d97c76a908d5f8af211/sqlite_utils/db.py#L1536-L1539

So perhaps .create_index() should grow an extra option that creates the index even if the name already exists, by finding a new name.

This is strange - the code already checks that an index doesn't exist before attempting to create it: https://github.com/simonw/sqlite-utils/blob/92aa5c9c5d26b0889c8c3d97c76a908d5f8af211/sqlite_utils/db.py#L893-L902