Prefer strict tables in SQLite

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iingve about 21 hours ago 162 commentsRead Article on evanhahn.com

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simonw•about 15 hours ago

> Unfortunately, I don’t think there’s a way to ALTER a table to make it strict. I think you have to copy the data out of the non-strict table into the strict one.

This inspired me to add a feature to my sqlite-utils Python library and CLI tool, so you can now use it to transform non-strict tables to strict (and vice-versa) like this:

  uvx sqlite-utils transform data.db mytable --strict

Or in Python:

  import sqlite_utils

  db = sqlite_utils.Database("data.db")
  db.table("mytable").transform(
    strict=True
  )

Release notes for 4.1 here: https://sqlite-utils.datasette.io/en/stable/changelog.html#v...

Here are the relevant docs:

- Using table.transform(strict=True): https://sqlite-utils.datasette.io/en/stable/python-api.html#...

- The sqlite-utils transform command: https://sqlite-utils.datasette.io/en/stable/cli.html#transfo...

throwlifeaway•2 minutes ago

> This inspired me to add a feature to my sqlite-utils Python library

"me" == "ChatGPT", apparently:

> Can the .transform() internal Python method turn a non-strict table into a strict table?

> No. Table.transform() preserves the table’s existing strictness; it cannot change it. Its signature has no strict= parameter

> add an optional strict= boolean parameter to the transform() method - if it is None (the default) then the strict is not changed, otherwise True means change to strict and False means change to non strict. Implement with red/green TDD and uv run pytest -k

https://gist.github.com/simonw/ab8256b81646ad967a601975e206d...

I appreciate the transparency, at least.

OskarS•about 4 hours ago

Does this trick work with foreign keys? Like, if you have an ON CASCADE DELETE, does it delete a bunch of rows in other tables when converting the table to strict?

simonw•about 3 hours ago

It uses "PRAGMA foreign_keys=0" and "PRAGMA defer_foreign_keys= ON" before running the transformation, then resets those settings afterwards: https://github.com/simonw/sqlite-utils/blob/3f0471701b5f8c7d...

That's the pattern recommended by SQLite here: https://www.sqlite.org/lang_altertable.html#otheralter

simonw•about 3 hours ago

Thanks for the nudge, I just added a new test explicitly covering this: https://github.com/simonw/sqlite-utils/commit/d71420065903ff...

dfabulich•about 16 hours ago

https://sqlite.org/flextypegood.html explains why this isn't the default (and probably will never be the default).

> rigid type enforcement can successfully prevent the customer name (text) from being inserted into the integer Customer.creditScore column. On the other hand, if that mistake occurs, it is very easy to spot the problem and find all affected rows.

That doesn't line up with my experience. (In particular, it may not be easy to fix those corrupted rows; the data may be entirely lost.)

> By suppressing easy-to-detect errors and passing through only the hard-to-detect errors, rigid type enforcement can actually make it more difficult to find and fix bugs.

This doesn't line up with my experience at all.

tyre•about 13 hours ago

These are similar to arguments that people made about MongoDB. You can store anything! And then most people who used it realized that this is actually terrible, in most cases.

It looks like this is an artifact of when SQLite was written and the strong opinion of its author, less so a rigorous engineering principle. Reading this, it sounds like the author has been criticized a lot on this, is digging in their heels no matter what, and will find any supposed justification.

On the other hand, datatypes like JSON or HSTORE (in postgres) can handle what they are advocating for. But opt-in to YOLO typing is nearly always better than opt-out.

zvrba•about 10 hours ago

I've seen a set of SQL tables designed to mimic "flexible classes". There's a table for the "class", another table defining its "fields", and two other tables defining class instances and related field values (all as varchar).

Flexible, yes. You can store anything. The downside is, that I've also found "anything". Stuff attached to the wrong "class", wrong datatypes, missing "obligatory" fields, etc, etc.

It's a PITA to work with. If I could design it from scratch, it'd be a single table with JSON payload.

fauigerzigerk•about 3 hours ago

>It's a PITA to work with. If I could design it from scratch, it'd be a single table with JSON payload.

Isn't plain JSON even worse? At least the design you're criticising has a dynamic schema definition separate from code.

You could of course have a JSON schema somewhere, but in my experience the whole point of representing the schema as data in the database is to support (limited) end-user driven schema changes.

I would use JSON to store data that complies with a schema that can be modified by third parties outside of my control.

port11•about 9 hours ago

The safety and trust that comes out of a very reliable database setup is, apparently, a misplaced feeling that makes data bugs harder to fix. I really don’t understand their take.

My experience is the opposite: add as many checks and safety rails to <DB> (Postgres, in my case), and you don’t have to go looking for this sort of mistake, which shouldn’t happen in the first place.

HexDecOctBin•about 3 hours ago

SQLite did come from TCL everything-is-a-string world, so this attitude is not surprising. TCL makes for a very good shell language (much better than Bash or Batch), but a rigid systems language it is not.

ivanjermakov•about 5 hours ago

Wow, SQLite not believing in fail-fast systems is disappointng. Never knew SQLite was JS of SQL!

fauigerzigerk•about 2 hours ago

That doesn't do justice to some of the arguments that SQLite authors are making.

In Postgres, if you insert a real number into an int column, the data gets rounded and stored as int. In SQLite, the data is inserted as real.

Neither approach is fail-fast.

IshKebab•about 4 hours ago

Yeah that doesn't make any sense at all. It sounds like a post-hoc justification to me.

> If you find a real-world case where STRICT tables prevented or would have prevented a bug in an application, please post a message to the SQLite Forum so that we can add your story to this document.

Kind of wild that they don't believe this happens.

Also they totally drew the wrong conclusions from their example in Appendix A. The data type was CHECK'd for a column and they are like "oh if only we hadn't enforced checks of this data type, we would have had to verify it when we opened the database!" instead of "thank goodness we have this CHECK'd this data type, it means we are forced to robustly verify it in one place, instead of using unreliable checks in the application code".

jll29•about 20 hours ago

I'd like to see STRICT as the default.

That's pretty much the only disagreement with the SQLite developer, who is an amazing guy that wrote an amazing tool!

Rendello•about 16 hours ago

Even foreign keys aren't enabled by default, you have to use `PRAGMA foreign_keys = ON;` [1]. The bigger issue with strict tables is that there is no equivalent pragma, and you're forced to use the non-standard STRICT on each CREATE TABLE. A global STRICT pragma was considered but not implemented, see this forum thread [2].

1. https://sqlite.org/foreignkeys.html

2. https://sqlite.org/forum/forumpost/1b9d073a37ca5998

lenkite•about 7 hours ago

SQLite has a LOT of footguns that one only discovers over time. Dynamically typed by default, Off-by-Default foreign keys, ID re-use in AUTOINCREMENT, WAL Mode needing explicit enabling to ensure readers are not blocked, double-quote/single-quote issues, positional placeholders & named parameters issues, no TIMESTAMP type in 2026 despite being a CORE feature in SQL-92 standard, etc.

bhaak•about 4 hours ago

I knew most of he issues that you mentioned ... but 'ID re-use in AUTOINCREMENT'?

What the ...?

cowboylowrez•about 2 hours ago

"Enforce authoritarian type-checking when inserting new content into tables" lol you can really get into the mindset by reading these threads. I think having the strict defaultable at the database level seems like a good option, maybe they think everyone will pile into the new default and leave the old databases in a state of decaying disrepair?

My only experience with versionitus type things is with microsoft sql and other "enterprisey" things that used it and its hard enough without huge upgrade blockers like text in an integer field lol still they're willing to add the default to the table create statement. I'm thinking that sqlite folks feel that things like type safety, database consistency are disliked authoritarian attributes, and I'm sure thats a consideration in letting old code touch databases that old code doesn't understand.

Its wierd that they didn't like having a pragma for any new table creation even at the database level but they allow this problem factory:

  "Because of a quirk in the SQL language parser, versions of SQLite prior to 3.37.0 can still read and write STRICT tables if they set "PRAGMA writable_schema=ON" immediately after opening the database file, prior to doing anything else that requires knowing the schema."

https://github.com/simonw/sqlite-utils/issues/344#issuecomme...

I guess for ID reuse a rationalization could be that theres only so many integer values that can fit into a certain number of bytes haha

simonw•about 20 hours ago

SQLite very rarely changes defaults because of their commitment to backwards compatibility. They don't want software written against SQLite 3.53 to start throwing errors when upgraded to 3.54 because suddenly `CREATE TABLE` is creating strict tables and the rest of the software breaks as a result.

boredatoms•about 18 hours ago

The need ‘default sets’ so that as the very first command I can say ‘use 2026.1 defaults’

krick•about 16 hours ago

Or even better just SET STRICT_TABLES, or whatever other opt-in feature you want. A couple of such statements in the beginning of your migration script (refactored in a way to be reused across all migration scripts) and you are done. I wouldn't want to learn WTF "2026.1 defaults" are.

ezst•about 19 hours ago

Which seems reasonable. And those who care deeply will have no problem configuring it the specific way they want on their own project. Win-win.

sinfulprogeny•about 19 hours ago

Unless you don't know it exists of course

Asooka•about 18 hours ago

Well no, the software should be configured in its best state by default. Otherwise you run into the case where the user has to read the documentation like a legal contract to find all the footguns that need disabling. If STRICT is strictly better, than that should be the default. The correct approach here would be for the user to pass along a "compatibility version" tag when first connecting, which would set the defaults to whatever was default in that version. That should be something you force each user to set in their source and it should never ever have a "latest" value. It may be too late for sqlite, but if I were designing an API that had to remain stable for decades now, I would put an enum with possible versions in a header and require the user to pick one.

inigyou•about 18 hours ago

They already had this concern with WITHOUT ROWID. They recommend using WITHOUT ROWID whenever possible, but can't make it the default.

formerly_proven•about 18 hours ago

The SQLite documentation doesn't say that. WITH and WITHOUT ROWID tables are also different data structures (ordinary tables are B+ trees, without rowid B*). In particular, without rowid tends to be detrimental for tables consisting of wide rows, while being an advantage for narrow rows with a non-integer key.

ahartmetz•about 19 hours ago

There are more similar issues, like disabling foreign key constraints by default "for compatibility reasons". Makes me wonder if there was a time when SQLite supported foreign key syntax, but didn't actually implement the functionality.

formerly_proven•about 19 hours ago

> This document describes the support for SQL foreign key constraints introduced in SQLite version 3.6.19 (2009-10-14).

ahartmetz•about 19 hours ago

That quote leaves open whether SQLite "pretended" to support foreign keys by allowing to create tables with them, but didn't implement them. Otherwise, I don't see the compatibility problem.

panzi•about 18 hours ago

Well, I would also like a proper datetime/timestamp datatype that isn't just a string.

sheept•about 15 hours ago

Why not store them as integers? Representing dates is a UI responsibility

nullisland00•about 9 hours ago

Forcing all dates to be cast to a single time zone (UTC) complicates workflows when you’re on the other side of the globe. Many DBs have added a timestamp offset type for this to keep the data in the offset it occurred in.

panzi•about 14 hours ago

I also want to be able to debug the database in an SQL console with nice looking date-times.

echelon•about 18 hours ago

Someone should fork it in Rust using Claude and rename it SQRite.

Strict type all the things.

redman25•about 17 hours ago

A large portion of the tests are closed source unfortunately which would make it tough to create a port.

estebank•about 16 hours ago

https://github.com/tursodatabase/turso

edoceo•about 17 hours ago

Why not ~Zoidberg~ Zig?

mort96•about 20 hours ago

Yeah it's a really weird design decision. Why would I want the database to let me accidentally insert the wrong type? SQLite is mostly great but its philosophy towards type safety leaves something to be desired. I once had to clean up in a project where someone had accidentally stored the strings '1' and '0' in a Boolean column in code deployed to thousands of devices; not fun.

Another thing I dislike is the lack of timestamp types. Instead, you're expected to just use a text column and store a textual timestamp. Even worse, instead of using ISO, the standard date time functions produce strings on the form "yyyy-mm-dd HH:MM:SS" which you're just supposed to assume are in UTC. Why not at least give us "yyyy-mm-ddTHH:MM:SSZ"? Or, you know, a proper space efficient timestamp data type.

A truly great project, with some truly baffling design decisions.

masklinn•about 20 hours ago

> Instead, you're expected to just use a text column and store a textual timestamp.

You can actually use an integer column and store Unix timestamps (or floats for subsecond accuracy).

But yes, sqlite has very little types support and its default behaviour is very much unityped / dynamically typed which I also dislike. Same with having to enable foreign keys every time you open a connection.

mort96•about 6 hours ago

Of course you can store timestamps as integers, but then you lose sqlite's built-in date and time functions.

ncruces•about 19 hours ago

Only if you're not compiling yourself, otherwise, there's SQLITE_DEFAULT_FOREIGN_KEYS=1

3eb7988a1663•about 19 hours ago

'0' and '1', while not ideal, seems fine to maintain? There is not even a true SQLite boolean type.

Then again, I have been subjected to Oracle nonsense for too long and have had to accept all of the boolean alternatives: 0,1,'0','1',Y,N,y,n,YES,NO,T,F, etc

chasil•about 15 hours ago

When you need many booleans on a table, use an integer with bitwise and/or to record them as powers of 2.

I have done this many times. Function-based indexes are necessary if they must be searched.

mort96•about 6 hours ago

When the column is an integer column, you don't want strings in it.

bbkane•about 18 hours ago

the SQLite team explains their preference for dynamic types here: https://sqlite.org/flextypegood.html

(please note that I personally strongly prefer static types, but I still found this an interesting read).

cowboylowrez•about 3 hours ago

"SQLite began as a TCL extension that later escaped into the wild." case closed, everything else is a rationalization but who doesn't like a good rationalization every now and then?

formerly_proven•about 19 hours ago

If every time the SQLite team added a better default for something they changed it, we'd be at SQLite 11 by now and every application would contain at least six incompatible versions of SQLite.

win311fwg•about 19 hours ago

If you are using SQLite as an embedded database, which seems to be SQLite's primary use-case, why wouldn't you prove statically that you are not accidentally inserting the wrong type? Runtime checks are unnecessary overhead.

Runtime validation is there to enable when using SQLite in other ways.

Animats•about 16 hours ago

Yes. I always considered that a downside of SQLite. You have to validate numeric fields on the read side or risk the application blowing up on bad data.

m0nacle•about 14 hours ago

lmao default okay buddy

neverartful•about 19 hours ago

I agree with you. I'd go one step further and let it be the only mode available starting with new versions of the library.

ezekiel68•about 17 hours ago

Coming from the enterprise SQL world, I never took SQLite seriously for the very reason that field types were not enforced by default. (Yes, I was agog when it became the backbone for app metadata on smartphones.) Anyway, reading this reminds me of the old chestnut from networking about choosing UDP over TCP for its low-latency and simplicity and then eventually adding nearly all the reliability facilities of TCP to the app (automatic retry, etc) by hand.

nine_k•about 17 hours ago

The difference is that when you add all these mechanisms yourself, you can do it differently than TCP does, sometimes to a great effect: see QUIC and HTTP/3.

OTOH I don't see a similar superpower arising from handcrafted data type enforcement over (non-strict) SQLite.

astrobe_•about 5 hours ago

Yep. More generally the correct reason to prefer UDP over TCP is the fine-grained control you gain. When you want that and have to use TCP, you're in for a deadly fight against the OS and its TCP/IP stack.

Datagram is also quite often more fit for applications than streams, because many applications are message oriented. The Websocket protocol acknowledges that even though over TCP. But that's more a bonus point than a strong reason to choose UDP over TCP, one can always recreate packets/messages on top of TCP. It's a bit goofy though, because TCP uses IP packets.

A lot of online games with significant real-time constrains and many-to-many connections gladly use UDP - and similarly, video conference services also use it. Smaller protocols like DNS and NTP as well.

There are other arguments beside real-time streaming with acceptable data loss, see [1] and the "end-to-end argument" paper it links in particular.

Choosing UDP and ending up recreating some of its reliability and flow control features is not a "Uh, Oh..." moment. It's normally a deliberate choice. Sometimes you do need custom wheels [2].

[1] https://deepplum.com/post-b/

[2] https://en.wikipedia.org/wiki/Mecanum_wheel

Rendello•about 16 hours ago

Even foreign keys weren't available before 2009, and are still not enabled by default:

https://sqlite.org/foreignkeys.html

akoboldfrying•about 12 hours ago

Thanks, I've been using SQLite for a while and I did not realise that FKs are disabled by default! Fortunately not on anything critical, still... Yikes.

noisy_boy•about 13 hours ago

> Anyway, reading this reminds me of the old chestnut from networking about choosing UDP over TCP for its low-latency and simplicity and then eventually adding nearly all the reliability facilities of TCP to the app (automatic retry

Sometimes you can build a successful business out of doing so: https://aeron.io/

ezekiel68•about 10 hours ago

For sure -- but these are the 'exceptions that prove the rule'. Someone else mentioned HTTP3 and QUIC. For all of these, there are thousands of projects (including multiplayer games and even enterprises) that didn't quite get it right and suffered for it.

Or, at least, so says the lore.

Rohansi•about 16 hours ago

> I never took SQLite seriously for the very reason that field types were not enforced by default.

I can understand not taking it seriously if it was completely unsupported but I'm pretty sure most databases don't have perfect default configs. Even PostgreSQL needs configuration for optimal performance because the defaults are for low (minimum) spec systems.

> then eventually adding nearly all the reliability facilities of TCP to the app (automatic retry, etc) by hand.

Depending on what you're doing you're still probably doing better than TCP after all that work. TCP is a stream based protocol which is not ideal for many applications due to head of line blocking. If you built your own reliability layer over UDP you likely avoid that issue entirely.

lacunary•about 16 hours ago

tuning defaults for performance feels much more acceptable than tuning defaults for correctness

Rohansi•about 13 hours ago

It's for backwards compatibility, as always. You also need to enable foreign keys or they aren't enforced. You also need to tune for performance (enable WAL, adjust cache size, etc.).

The SQLite documentation is very up front about these things [1] and more. It should only be an issue if you're the type of person who never reads any documentation.

[1] https://sqlite.org/quirks.html

pavon•about 15 hours ago

It wasn't option for the first 20 years of SQLite's existence.

762236•about 16 hours ago

If I'm interested in a Jeep or Bronco, I don't go to a car reviewer. They say it is noisy and handles poorly. They act like their use case is what matters for something obviously targeting a different use case.

chrismorgan•about 11 hours ago

I don’t like strict mode because it quite unnecessarily thwarts better strict types in the application layer: by restricting the spellings of column types, it stops you from using more meaningful names and prevents code from using those names when mapping database and application types:

https://hn.algolia.com/?query=chrismorgan+strict+sqlite&type...

If you’re going to work with a database through something like the Rust sqlx crate, I think you’re better to eschew strict mode.

ncruces•about 2 hours ago

Precisely, this is my experience as well.

If you use strict tables with my Go SQLite driver, you'll get worse support for bool/date/time columns than otherwise.

It's still unfortunate though that typing a column DECIMAL triggers numeric affinity, which destroys decimal numbers stored as strings.

petilon•about 20 hours ago

The downside of strict tables is that some data types are not available, such as Date.

Strict should really be the default. If a database is shared by multiple applications then you should be able to rely on the declared data type. If one application stores a string into a numeric column that breaks everyone else.

On the other hand, the main use case for SQLite is embedded databases. And that means only one application is using the database. In that scenario being able to evolve the schema (as opposed to creating a new database and copying the data over) can be seen as an advantage. The application's code knows what to expect in each column--including mixed data types.

e2le•about 19 hours ago

> The downside of strict tables is that some data types are not available, such as Date.

There are only 5 datatypes in sqlite. INTEGER, TEXT, BLOB, REAL, and NUMERIC.

https://sqlite.org/datatype3.html

petilon•about 18 hours ago

Right, and that's the problem. There should be DATE and BOOL as well, especially in strict mode.

mort96•about 6 hours ago

I don't understand what this has to do with strict mode? Yes those types should exist, but the workaround is to use an integer column for bool and a text column for date, whether or not you're using strict mode.

asa400•about 11 hours ago

Yeah the parse rules for strict tables are annoying but it doesn't change the underlying semantics:

  sqlite> create table test (
    id integer primary key,
    created_at text default current_timestamp,
    flag integer not null default 0 check (flag in (0, 1))
  ) strict;
  sqlite> insert into test (flag) values (1);

  sqlite> select * from test;
  ╭────┬─────────────────────┬──────╮
  │ id │     created_at      │ flag │
  ╞════╪═════════════════════╪══════╡
  │  1 │ 2026-07-12 04:03:22 │    1 │
  ╰────┴─────────────────────┴──────╯

masklinn•about 19 hours ago

numeric is not a type it’s an affinity, the underlying types are real and integer. That is why numeric is not valid on strict tables.

ncruces•about 19 hours ago

The downside is that you loose the place to store the metadata that a column is supposed to store a date.

Which is why I prefer not to use them.

masklinn•about 7 hours ago

A comment will do more than a nonsensical type which is not enforced: it won’t have the wrong affinity, it will spell out what the concrete type is, and there’s no limit to what it can specify.

Domain types would be the best fix, but I do not think legacy tables are the second best.

Ciantic•about 20 hours ago

SQLite has no date data type. Also SQLite has no way to call EXPLAIN on query and get the dummy type name either for arbitrary SELECT query, so you can't even infer it, if you were to use the dummy type name "DATE" or "DATETIME".

masklinn•about 19 hours ago

> some data types are not available, such as Date.

That’s not a type, you just get a numeric-affinity column.

petilon•about 18 hours ago

Right, and that's a serious limitation when in strict mode.

masklinn•about 9 hours ago

The serious limitation is that you create a column as date, you don’t understand what sqlite does with it, and you start storing strings in there, at which point everything is confused.

You can use comments to preserve intent in strict mode, and that’s strictly more useful than fuzzy mode: it is richer, it is clearer, and it is no less reliable.

frollogaston•about 18 hours ago

Yeah my DB is the one place I want strict types. Well also RPCs. But SQLite is a somewhat different set of use cases, so maybe I'd understand https://sqlite.org/flextypegood.html more if I were using it. Like there's a point about random scripts not made for SQLite happening to work with it, which isn't normally a consideration for other DBMSes.

petilon•about 16 hours ago

> https://sqlite.org/flextypegood.html

Both the advantages and disadvantages section is missing key arguments.

Key argument in favor of flexible typing: Easy to evolve schema. When you are using SQLite to store data in your embedded database and your requirements change, do you want to create a new database and migrate data each time? Evolving the schema in-place is much easier, and if your application is the only one reading/writing data into the database you will not be surprised by the fact the column that previously stored integers now contains strings as well.

Key argument against flexible typing: The schema is a contract, and when multiple applications read and write to a single database, and these applications are updated on their own schedules, storing the wrong type of data in a column will break the other applications. Strict adherence to the contract is necessary for applications to collaboratively read and write data. When a table is created by one application and used by another, the data types must be what you agreed to.

_flux•about 5 hours ago

I can see that it would be difficult to make changes to db schema types, if there are multiple separate applications with their own release schedule. But this affects schema structure as well, not just its types. I can't even describe how difficult it would be to write apps that work in that scenario—and test it against data that could be written into the db by any previous version of the app. If you truly have this kind of situation at hand, perhaps a document database would be a better fit.

Additionally, how often are there multiple apps with different release schedules written using Sqlite? I would expect overwhelmingly large number of its use cases would be a single application working on it.

frollogaston•about 14 hours ago

Can't say I've done a SQLite migration before. Changing int col to text in Postgres could be done with a couple of ALTER statements, or more safely, add a new col with a different name and switch over.

win311fwg•about 17 hours ago

> Yeah my DB is the one place I want strict types. Well also RPCs.

Which is why in most cases you are going to show at compile time that your code adheres to the typed structure. The SQLite schema you are developing alongside provides the type information for static analysis. There is no real benefit in also double checking again at runtime. Your code isn't going to magically mutate in a way that it starts inserting integers where your static analysis showed that it inserts strings.

SQLite is not like Postgres, which is designed for many different applications all sharing the same data, where you have to place trust in third-parties to also do the right thing. Runtime validation is critical in that environment. SQLite is designed for one application, one database. While it technically can support multiple applications sharing the same file, support is poor and it is not really designed for that. In the typical case, the only trust you need is your code, which you can evaluate at compile time. For the atypical cases you can enable strict tables.

frollogaston•about 14 hours ago

But one DB one app is fairly common with Postgres too, particularly if you're adhering to a services deliniation. Guess if your code enforces types at DB insert time, the DB doesn't need to, but one of those is more likely to change than the other.

win311fwg•about 12 hours ago

> But one DB one app is fairly common with Postgres too

That is common today, but remember that Postgres is now 40 years old. It is so old that it was originally based on QUEL rather than SQL. Back then database servers were designed to be what we now think of as the "API server". That necessitates runtime input validation same as your "API server" needs input validation today. If you were designing Postgres from scratch now you would do a lot of things differently, but it was built for its time.

> Guess if your code enforces types at DB insert time

It would be unusual for your programming language to magically turn strings into ints, or the like, so you can prove statically that your code won't insert the wrong thing. Duplicating the same thing at runtime doesn't buy you anything. Maybe if you are still trying to futz around with Javascript, but SQLite was designed for statically-typed programming languages.

rjrjthtrjrj•about 15 hours ago

2004 called and they want their ignorant bad takes back

coldtea•about 15 hours ago

They also want this type of joke and misunderstanding SQLite purpose to get "macho programmer" points back.

frollogaston•about 15 hours ago

Reddit called and said they're missing a guy

blixt•about 20 hours ago

I think I can see how dynamic data types make sense (eg flat key/value store), but my question would be:

What is least surprising? That INTEGER implicity accepts 'hello world' without error, or that you can't insert such a value unless you use a keyword like NONSTRICT or a type like ANY?

I would wager the vast majority of SQLite users if asked would probably not expect it to work.

frollogaston•about 14 hours ago

It's probably because SQLite intends to be untyped but also wants the statements to look like standard SQL. This matches their other note about wanting code designed to work with other DBMSes to accidentally work with SQLite too.

Otherwise, yeah, it's very surprising to explicitly put INTEGER and still be able to insert text. It's not like the user left the type out.

bch•about 19 hours ago

I had a UUID (partly?) mis-converted to a number if the UUID started w (from memory) something like 08123… which was parsed as octal. Confusing, annoying, fixed w “strict” and a complete table rebuild.

gunapologist99•about 18 hours ago

That was your language's driver "helping" you. There is no SQLite octal type.

bch•about 17 hours ago

I'll see if i can find the case - my description was a bit hand-wavy because it was a while ago, and just drawing on memory -- not that your explanation couldn't be true, but I thought I exercised that possibility. For your part, you'll remain sceptical it wasn't the driving language when I tell you it was Tcl, which is indeed the origin of this "manifest type" we're discussing :)

bch•about 13 hours ago

I can't replicate atm, but I now think it had to do w scientific notation, not octal - so "1e234..." into a text column. And istr "strict" solving my problem, but...

pettijohn•about 16 hours ago

CREATE TABLE ... STRICT WITHOUT ROWID is my default, I don't know why I'd ever do otherwise.

eternauta3k•about 8 hours ago

Why without Rowid? Are you using non-integer primary keys?

cdmckay•about 20 hours ago

I would’ve thought this was the default.

tehlike•about 20 hours ago

It really should be default, but it isn't due to backward compatibility (i assume).

poidos•about 20 hours ago

It’s a stated [0] goal of the project:

> SQLite strives to be flexible regarding the datatype of the content that it stores.

[0]: https://sqlite.org/stricttables.html

masklinn•about 19 hours ago

You can be flexible with strict tables, type every column as ANY and you pretty much get back the original behaviour.

poidos•about 19 hours ago

Sure, but you lose the representation of the developer’s intention that way. I would be pretty pissed off if I inherited a project and the schema was all ANYs.

tehlike•about 9 hours ago

Postgres is flexible, too. Sometimes design choices are just bad, and it's ok.

tuvix•about 20 hours ago

I’m kind of curious why the decision to have implicit casting like this was made in the first place. I can’t think of a single upside other than not having to type out cast(foo as bar)

rogerbinns•about 20 hours ago

SQLite was originally started as a local database library for use during development for times when the main networked database was not available. It used dbm as the underlying storage mechanism, with the dbm API roughly being string keys with string values. ie all underlying values were actually stored as strings. The SQLite code would automatically do conversions - eg the plus operator would convert the strings to int or float, add them, and generate a stringified number as a result. The vast majority of implementation code did not have to care about types, and very local decisions could be made such as in the addition example.

TCL was used as a dev wrapper language at the time, and it functioned the same way.

It was only in mid-2004 that SQLite 3 was released which used its own storage backend, and that allowed for the 5 supported storage types (int64, string, bytes, float, null). It was API compatible (with minor adjustments) with the earlier SQLite 2, so the lack of static typing continued, otherwise everyone would have to rewrite their code. You do get dynamic typing, which hasn't been a problem for the vast majority of SQLite users.

Do remember that SQLite is competition for fopen, not Oracle / Postgres etc. It is trying to make things as effective as possible in that scenario. If you don't want numbers in your string column, then don't do that!

somat•about 15 hours ago

If I remember correctly mysql also started with a berkeleydb(dbm) storage layer. before myisam then later innodb.

I used to sort of dismiss berkeleydb(why so simple?), but a disk backed b-tree indexed key value store is not trivial to get right and having a prebuilt library to do it provides a huge value.

notRobot•about 20 hours ago

SQLite docs: The Advantages Of Flexible Typing: https://sqlite.org/flextypegood.html

mb7733•about 19 hours ago

It's even worse than implicit casting, if the value can't be cast to the the column's type, it's just inserted without casting. Eg. into an integer column, '10' -> 10 and '1O' -> '1O'

rogerbinns•about 19 hours ago

That is documented behaviour - think of it as making a best effort, and not losing the value.

As of January 2006 you could add CHECK constraints using the TYPEOF function to reject that at the SQL level. And it is your own code - there is no server - doing the insertions. As was common back then, protecting you from your own bugs was not a high priority for APIs!

pstuart•about 20 hours ago

IIRC, the project started out as TCL code and it carried that vibe through to what it is today.

dzonga•about 19 hours ago

the only thing that sucks about SQLite is migrations.

bbkane•about 18 hours ago

Yes, the process at https://www.sqlite.org/lang_altertable.html is super risky - 12 steps and a giant CAUTION sidebar about the data loss possible if you do it incorrectly.

They DO include a nice section at the bottom about why these limitations exist, but I wish they would make the process easier.

wmanley•about 17 hours ago

We use this for migrations: https://david.rothlis.net/declarative-schema-migration-for-s...

Discussed here: https://news.ycombinator.com/item?id=31249823

But it would be a lot better if it were built in.

Cyberdog•about 19 hours ago

If you're stuck with an older version of SQLite and/or want to enforce order on an existing table without creating a new table with STRICT and then copying all your rows over and/or also want to do things like enforce signedness, int size, or char/varchar length on a field like you can in other DBs, you can use CHECK constraints.

  CREATE TABLE users (
    user_id CHAR(36) NOT NULL PRIMARY KEY CONSTRAINT user_id_length CHECK (LENGTH(user_id) = 36),
    email_address VARCHAR(255) UNIQUE CONSTRAINT email_address_length CHECK (email_address IS NULL OR LENGTH(email_address) < 256),
    role UNSIGNED TINYINT(1) NOT NULL CONSTRAINT role_valid CHECK (role >= 0 AND role <= 9)
  )

Note that the column types here are just to describe to the user what the field should be doing and it's the constraints that actually enforce it. Behind the scenes SQLite still creates two "text (supposedly but whatever)" and one "integer (supposedly but whatever)" columns.

It's a little frustrating that all this extra cruft is necessary to get the world's most popular RDBMS to take data correctness seriously. I hope that some SQLite fork that behaves more like other RDBMSes when it comes to this stuff catches on some day, but the fact that that hasn't happened yet makes me think that the demand isn't there, somehow, unfortunately.

https://sqlite.org/lang_createtable.html#ckconst

sgarland•about 14 hours ago

Wait until you read about its quirks [0]. My favorite:

“NUL characters (ASCII code 0x00 and Unicode \u0000) may appear in the middle of strings in SQLite. This can lead to unexpected behavior.”

0: https://sqlite.org/quirks.html

wvenable•about 9 hours ago

I was going to say that really shouldn't be a problem but then I read further:

https://sqlite.org/nulinstr.html

cowboylowrez•about 2 hours ago

Yeah the fact that length() can't count null containing strings accurately is interesting.

nektro•about 16 hours ago

thanks! i have seen the sqlite quirks page before but just added this to my queries thanks to you

quotemstr•about 17 hours ago

It's good advice to "Prefer strict X in Y" for almost any value of X and Y. Lax DWIM stuff always comes back and bites you in the end.

nine_k•about 16 hours ago

"Everything should be built top down, except for the first time", as the saying goes %) The problem is often that new things are built with tools that allow for flexibility, because the builder hasn't decided on the shape of what needs to be built. In 1990s it was Perl, in 2020s it's vibe-coding, but in either case it's lax and "dwim".

As the developer attains a much better understanding of the product, strictness becomes more and more beneficial, but the spectre of backwards compatibility haunts the interfaces and defaults.

Leeann1951•about 11 hours ago

I want a better alternative for SQLite

moron4hire•about 20 hours ago

Using Entity Framework, this doesn't come up as a particular issue, but I still wish it were strict by default because I expect there could be some performance optimizations made for de/serialization.

Eswo•about 20 hours ago

really interesting, thanks

itsthecourier•about 20 hours ago

about the use of ANY, that's perfect for tracking changes on an audit table per field

coldtea•about 15 hours ago

Too many people missing the point entirely and wanting to make SQLite Postgres or Oracle.

frollogaston•about 14 hours ago

SQLite has to be one of the most stubborn software projects around, in a good way. Everything about it breaks what you learn in school and ignores trends, but it thrives.

First time I used it was in high school, when I was a newbie to C and didn't know how to link in libraries, and SQLite was the only thing that offered all the code as a single .c file https://sqlite.org/amalgamation.html

cowboylowrez•about 2 hours ago

I do understand the mindset, in college, math was pretty authoritarian in nature.

m0nacle•about 14 hours ago

i think braindead developers (most people in this thread) have become way too typescript pilled and as such think that types are something you can’t live without. grow up. use another of the 4000 databases out there or stop fucking bitching that you can’t manage your data without going peepee in your pampers

sherburt3•about 18 hours ago

I really hate this trend of turning every piece of software into this kafkaesque monstrosity that demands you jump through 100 hurdles to do the simplest thing. I mean yeah its good for LLMs but as a human it gets kind of annoying. I honestly love that if you hand SQLite garbage it will do its best.

m0nacle•about 14 hours ago

this 100%