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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 |
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1578790070 | I_kwDOCGYnMM5eGmy2 | 527 | `Table.convert()` skips falsey values | 167893 | closed | 0 | 5 | 2023-02-10T00:00:52Z | 2023-05-09T21:15:05Z | 2023-05-08T21:03:24Z | CONTRIBUTOR | # Summary By design, `Table.convert()` does [not attempt](https://github.com/simonw/sqlite-utils/blob/fc221f9b62ed8624b1d2098e564f525c84497969/sqlite_utils/db.py#L2663) conversion of falsey values (`None`, `""`, `0`, ...). This is surprising (directly contradicts the docstring) and `convert()` may quietly skip cells where the user assumed a conversion would take place. # Example Increment a column of integers by one ``` python from sqlite_utils import Database db = Database(memory=True) table = db['table'] col = 'x' table.insert_all([{col: 0}, {col:1}]) print(table.get(1)) # 0 print(table.get(2)) # 1 print() table.convert(col, lambda x: x+1) print(table.get(1)) # got 0, expected 1 ⚠⚠⚠ print(table.get(2)) # got 2, expected 2 ``` Another example might be, say, transforming cells containing empty string to `NULL`. # Discussion This was, I think, a pragmatic choice so that consumers can skip writing guard clauses for these falsey values (particularly from the CLI). But this surprising undocumented behavior can lead to incorrect data. I don't think this is a good trade-off between convenience and correctness. In the absence of this convenience users will either have to write guard clauses into their conversion expressions (or adapt the called function to do the same), so: ``` python fn(value) if value else value ``` instead of: ``` python fn(value) ``` This is more typing and sometimes I will forget, and there will be errors. (But they will be noisy errors, which is a good thing). Such a change will certainly inconvenience some existing consumers; there will be some breakage. But I think this is worth it to avoid quietly not converting some values by default, which can lead to quietly bad data. I have a PR that I will attach, please take a look and see what you think. | 140912432 | issue | { "url": "https://api.github.com/repos/simonw/sqlite-utils/issues/527/reactions", "total_count": 0, "+1": 0, "-1": 0, "laugh": 0, "hooray": 0, "confused": 0, "heart": 0, "rocket": 0, "eyes": 0 } |
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1575131737 | I_kwDOCGYnMM5d4ppZ | 525 | Repeated calls to `Table.convert()` fail | 167893 | closed | 0 | 4 | 2023-02-07T22:40:47Z | 2023-05-08T21:59:41Z | 2023-05-08T21:54:02Z | CONTRIBUTOR | ## Summary When using the API, repeated calls to `Table.convert()` do not work correctly since all conversions quietly use the callable (function, lambda) from the first call to `convert()` only. Subsequent invocations with different callables use the callable from the first invocation only. ## Example ```python from sqlite_utils import Database db = Database(memory=True) table = db['table'] col = 'x' table.insert_all([{col: 1}]) print(table.get(1)) table.convert(col, lambda x: x*2) print(table.get(1)) def zeroize(x): return 0 #zeroize = lambda x: 0 #zeroize.__name__ = 'zeroize' table.convert(col, zeroize) print(table.get(1)) ``` Output: ``` {'x': 1} {'x': 2} {'x': 4} ``` Expected: ``` {'x': 1} {'x': 2} {'x': 0} ``` ## Explanation This is some relevant [documentation](https://github.com/simonw/sqlite-utils/blob/1491b66dd7439dd87cd5cd4c4684f46eb3c5751b/docs/python-api.rst#registering-custom-sql-functions:~:text=By%20default%20registering%20a%20function%20with%20the%20same%20name%20and%20number%20of%20arguments%20will%20have%20no%20effect). * `Table.convert()` takes a `Callable` to perform data conversion on a column * The `Callable` is passed to `Database.register_function()` * `Database.register_function()` uses the callable's `__name__` attribute for registration * (Aside: all lambdas have a `__name__` of `<lambda>`: I thought this was the problem, and it was close, but not quite) * However `convert()` first wraps the callable by local function [`convert_value()`](https://github.com/simonw/sqlite-utils/blob/fc221f9b62ed8624b1d2098e564f525c84497969/sqlite_utils/db.py#L2661) * Consequently `register_function()` sees name `convert_value` for all invocations from `convert()` * `register_function()` silently ignores registrations using the same name, retaining only the first such registration There's a mismatch between the comments and the code: https://github.com/simonw/sqlite-utils/blob/fc221f9b62ed8624b1d2098e564f525c84497969/sqlite_utils/db.py#L4… | 140912432 | issue | { "url": "https://api.github.com/repos/simonw/sqlite-utils/issues/525/reactions", "total_count": 0, "+1": 0, "-1": 0, "laugh": 0, "hooray": 0, "confused": 0, "heart": 0, "rocket": 0, "eyes": 0 } |
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1044267332 | I_kwDOCGYnMM4-PkFE | 336 | sqlite-util tranform --column-order mangles columns of type "timestamp" | 536941 | closed | 0 | 1 | 2021-11-04T01:15:38Z | 2023-05-08T21:13:38Z | 2023-05-08T21:13:38Z | CONTRIBUTOR | Reproducible code below: ```bash > echo 'create table bar (baz text, created_at timestamp default CURRENT_TIMESTAMP)' | sqlite3 foo.db > sqlite3 foo.db SQLite version 3.36.0 2021-06-18 18:36:39 Enter ".help" for usage hints. sqlite> .schema bar CREATE TABLE bar (baz text, created_at timestamp default CURRENT_TIMESTAMP); sqlite> .exit > sqlite-utils transform foo.db bar --column-order baz sqlite3 foo.db SQLite version 3.36.0 2021-06-18 18:36:39 Enter ".help" for usage hints. sqlite> .schema bar CREATE TABLE IF NOT EXISTS "bar" ( [baz] TEXT, [created_at] FLOAT DEFAULT 'CURRENT_TIMESTAMP' ); sqlite> .exit > sqlite-utils transform foo.db bar --column-order baz > sqlite3 foo.db SQLite version 3.36.0 2021-06-18 18:36:39 Enter ".help" for usage hints. sqlite> .schema bar CREATE TABLE IF NOT EXISTS "bar" ( [baz] TEXT, [created_at] FLOAT DEFAULT '''CURRENT_TIMESTAMP''' ); ``` | 140912432 | issue | { "url": "https://api.github.com/repos/simonw/sqlite-utils/issues/336/reactions", "total_count": 0, "+1": 0, "-1": 0, "laugh": 0, "hooray": 0, "confused": 0, "heart": 0, "rocket": 0, "eyes": 0 } |
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