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bda1e4e6ab
Relates to #127. This PR is still in draft and I have a few left things to do (tests, improve implementation), just opening it so anyone can track this work meanwhile. Closes #664
25 KiB
25 KiB
Compatibility with SQLite
This document describes the compatibility of Limbo with SQLite.
Table of contents:
Features
Limbo aims to be fully compatible with SQLite, with opt-in features not supported by SQLite.
The current status of Limbo is:
- ✅ SQLite file format is fully supported.
- 🚧 SQLite query language [status]
- 🚧 SQLite C API [status].
- ⛔️ Concurrent access from multiple processes is not supported.
SQLite query language
Statements
| Statement | Status | Comment |
|---|---|---|
| ALTER TABLE | No | |
| ANALYZE | No | |
| ATTACH DATABASE | No | |
| BEGIN TRANSACTION | No | |
| COMMIT TRANSACTION | No | |
| CREATE INDEX | No | |
| CREATE TABLE | Partial | |
| CREATE TRIGGER | No | |
| CREATE VIEW | No | |
| CREATE VIRTUAL TABLE | No | |
| DELETE | No | |
| DETACH DATABASE | No | |
| DROP INDEX | No | |
| DROP TABLE | No | |
| DROP TRIGGER | No | |
| DROP VIEW | No | |
| END TRANSACTION | No | |
| EXPLAIN | Yes | |
| INDEXED BY | No | |
| INSERT | Partial | |
| ON CONFLICT clause | No | |
| PRAGMA | Partial | |
| PRAGMA cache_size | Yes | |
| REINDEX | No | |
| RELEASE SAVEPOINT | No | |
| REPLACE | No | |
| RETURNING clause | No | |
| ROLLBACK TRANSACTION | No | |
| SAVEPOINT | No | |
| SELECT | Yes | |
| SELECT ... WHERE | Yes | |
| SELECT ... WHERE ... LIKE | Yes | |
| SELECT ... LIMIT | Yes | |
| SELECT ... ORDER BY | Yes | |
| SELECT ... GROUP BY | Yes | |
| SELECT ... HAVING | Yes | |
| SELECT ... JOIN | Yes | |
| SELECT ... CROSS JOIN | Yes | SQLite CROSS JOIN means "do not reorder joins". We don't support that yet anyway. |
| SELECT ... INNER JOIN | Yes | |
| SELECT ... OUTER JOIN | Partial | no RIGHT JOIN |
| SELECT ... JOIN USING | Yes | |
| SELECT ... NATURAL JOIN | Yes | |
| UPDATE | No | |
| UPSERT | No | |
| VACUUM | No | |
| WITH clause | No |
Expressions
Feature support of sqlite expr syntax.
| Syntax | Status | Comment |
|---|---|---|
| literals | Yes | |
| schema.table.column | Partial | Schemas aren't supported |
| unary operator | Yes | |
| binary operator | Partial | Only %, !<, and !> are unsupported |
| agg() FILTER (WHERE ...) | No | Is incorrectly ignored |
| ... OVER (...) | No | Is incorrectly ignored |
| (expr) | Yes | |
| CAST (expr AS type) | Yes | |
| COLLATE | No | |
| (NOT) LIKE | No | |
| (NOT) GLOB | No | |
| (NOT) REGEXP | No | |
| (NOT) MATCH | No | |
| IS (NOT) | No | |
| IS (NOT) DISTINCT FROM | No | |
| (NOT) BETWEEN ... AND ... | No | |
| (NOT) IN (subquery) | No | |
| (NOT) EXISTS (subquery) | No | |
| CASE WHEN THEN ELSE END | Yes | |
| RAISE | No |
SQL functions
Scalar functions
| Function | Status | Comment |
|---|---|---|
| abs(X) | Yes | |
| changes() | Partial | Still need to support update statements and triggers |
| char(X1,X2,...,XN) | Yes | |
| coalesce(X,Y,...) | Yes | |
| concat(X,...) | Yes | |
| concat_ws(SEP,X,...) | Yes | |
| format(FORMAT,...) | No | |
| glob(X,Y) | Yes | |
| hex(X) | Yes | |
| ifnull(X,Y) | Yes | |
| iif(X,Y,Z) | Yes | |
| instr(X,Y) | Yes | |
| last_insert_rowid() | Yes | |
| length(X) | Yes | |
| like(X,Y) | Yes | |
| like(X,Y,Z) | Yes | |
| likelihood(X,Y) | No | |
| likely(X) | No | |
| load_extension(X) | Yes | sqlite3 extensions not yet supported |
| load_extension(X,Y) | No | |
| lower(X) | Yes | |
| ltrim(X) | Yes | |
| ltrim(X,Y) | Yes | |
| max(X,Y,...) | Yes | |
| min(X,Y,...) | Yes | |
| nullif(X,Y) | Yes | |
| octet_length(X) | Yes | |
| printf(FORMAT,...) | No | |
| quote(X) | Yes | |
| random() | Yes | |
| randomblob(N) | Yes | |
| replace(X,Y,Z) | Yes | |
| round(X) | Yes | |
| round(X,Y) | Yes | |
| rtrim(X) | Yes | |
| rtrim(X,Y) | Yes | |
| sign(X) | Yes | |
| soundex(X) | Yes | |
| sqlite_compileoption_get(N) | No | |
| sqlite_compileoption_used(X) | No | |
| sqlite_offset(X) | No | |
| sqlite_source_id() | No | |
| sqlite_version() | Yes | |
| substr(X,Y,Z) | Yes | |
| substr(X,Y) | Yes | |
| substring(X,Y,Z) | Yes | |
| substring(X,Y) | Yes | |
| total_changes() | Partial | Still need to support update statements and triggers |
| trim(X) | Yes | |
| trim(X,Y) | Yes | |
| typeof(X) | Yes | |
| unhex(X) | Yes | |
| unhex(X,Y) | Yes | |
| unicode(X) | Yes | |
| unlikely(X) | No | |
| upper(X) | Yes | |
| zeroblob(N) | Yes |
Mathematical functions
| Function | Status | Comment |
|---|---|---|
| acos(X) | Yes | |
| acosh(X) | Yes | |
| asin(X) | Yes | |
| asinh(X) | Yes | |
| atan(X) | Yes | |
| atan2(Y,X) | Yes | |
| atanh(X) | Yes | |
| ceil(X) | Yes | |
| ceiling(X) | Yes | |
| cos(X) | Yes | |
| cosh(X) | Yes | |
| degrees(X) | Yes | |
| exp(X) | Yes | |
| floor(X) | Yes | |
| ln(X) | Yes | |
| log(B,X) | Yes | |
| log(X) | Yes | |
| log10(X) | Yes | |
| log2(X) | Yes | |
| mod(X,Y) | Yes | |
| pi() | Yes | |
| pow(X,Y) | Yes | |
| power(X,Y) | Yes | |
| radians(X) | Yes | |
| sin(X) | Yes | |
| sinh(X) | Yes | |
| sqrt(X) | Yes | |
| tan(X) | Yes | |
| tanh(X) | Yes | |
| trunc(X) | Yes |
Aggregate functions
| Function | Status | Comment |
|---|---|---|
| avg(X) | Yes | |
| count() | Yes | |
| count(*) | Yes | |
| group_concat(X) | Yes | |
| group_concat(X,Y) | Yes | |
| string_agg(X,Y) | Yes | |
| max(X) | Yes | |
| min(X) | Yes | |
| sum(X) | Yes | |
| total(X) | Yes |
Date and time functions
| Function | Status | Comment |
|---|---|---|
| date() | Yes | partially supports modifiers |
| time() | Yes | partially supports modifiers |
| datetime() | Yes | partially supports modifiers |
| julianday() | Partial | does not support modifiers |
| unixepoch() | Partial | does not support modifiers |
| strftime() | No | |
| timediff() | No |
Modifiers:
| Modifier | Status | Comment |
|---|---|---|
| Days | Yes | |
| Hours | Yes | |
| Minutes | Yes | |
| Seconds | Yes | |
| Months | Yes | |
| Years | Yes | |
| TimeOffset | Yes | |
| DateOffset | Yes | |
| DateTimeOffset | Yes | |
| Ceiling | No | |
| Floor | No | |
| StartOfMonth | Yes | |
| StartOfYear | Yes | |
| StartOfDay | Yes | |
| Weekday(N) | Yes | |
| Auto | No | |
| UnixEpoch | No | |
| JulianDay | No | |
| Localtime | Partial | requires fixes to avoid double conversions. |
| Utc | Partial | requires fixes to avoid double conversions. |
| Subsec | Yes |
JSON functions
| Function | Status | Comment |
|---|---|---|
| json(json) | Partial | |
| jsonb(json) | ||
| json_array(value1,value2,...) | Yes | |
| jsonb_array(value1,value2,...) | ||
| json_array_length(json) | Yes | |
| json_array_length(json,path) | Yes | |
| json_error_position(json) | Yes | |
| json_extract(json,path,...) | Partial | Does not fully support unicode literal syntax and does not allow numbers > 2^127 - 1 (which SQLite truncates to i32), does not support BLOBs |
| jsonb_extract(json,path,...) | ||
| json -> path | Yes | |
| json ->> path | Yes | |
| json_insert(json,path,value,...) | ||
| jsonb_insert(json,path,value,...) | ||
| json_object(label1,value1,...) | Yes | When keys are duplicated, only the last one processed is returned. This differs from sqlite, where the keys in the output can be duplicated |
| jsonb_object(label1,value1,...) | ||
| json_patch(json1,json2) | ||
| jsonb_patch(json1,json2) | ||
| json_pretty(json) | ||
| json_remove(json,path,...) | ||
| jsonb_remove(json,path,...) | ||
| json_replace(json,path,value,...) | ||
| jsonb_replace(json,path,value,...) | ||
| json_set(json,path,value,...) | ||
| jsonb_set(json,path,value,...) | ||
| json_type(json) | Yes | |
| json_type(json,path) | Yes | |
| json_valid(json) | ||
| json_valid(json,flags) | ||
| json_quote(value) | ||
| json_group_array(value) | ||
| jsonb_group_array(value) | ||
| json_group_object(label,value) | ||
| jsonb_group_object(name,value) | ||
| json_each(json) | ||
| json_each(json,path) | ||
| json_tree(json) | ||
| json_tree(json,path) |
SQLite C API
| Interface | Status | Comment |
|---|---|---|
| sqlite3_open | Partial | |
| sqlite3_close | Yes | |
| sqlite3_prepare | Partial | |
| sqlite3_finalize | Yes | |
| sqlite3_step | Yes | |
| sqlite3_column_text | Yes |
SQLite VDBE opcodes
| Opcode | Status |
|---|---|
| Add | Yes |
| AddImm | No |
| Affinity | No |
| AggFinal | Yes |
| AggStep | Yes |
| AggStep | Yes |
| And | No |
| AutoCommit | No |
| BitAnd | Yes |
| BitNot | Yes |
| BitOr | Yes |
| Blob | Yes |
| Checkpoint | No |
| Clear | No |
| Close | No |
| CollSeq | No |
| Column | Yes |
| Compare | Yes |
| Concat | No |
| Copy | Yes |
| Count | No |
| CreateIndex | No |
| CreateTable | No |
| DecrJumpZero | Yes |
| Delete | No |
| Destroy | No |
| Divide | Yes |
| DropIndex | No |
| DropTable | No |
| DropTrigger | No |
| EndCoroutine | Yes |
| Eq | Yes |
| Expire | No |
| Explain | No |
| FkCounter | No |
| FkIfZero | No |
| Found | No |
| Function | Yes |
| Ge | Yes |
| Gosub | Yes |
| Goto | Yes |
| Gt | Yes |
| Halt | Yes |
| HaltIfNull | No |
| IdxDelete | No |
| IdxGE | Yes |
| IdxInsert | No |
| IdxLT | No |
| IdxRowid | No |
| If | Yes |
| IfNeg | No |
| IfNot | Yes |
| IfPos | Yes |
| IfZero | No |
| IncrVacuum | No |
| Init | Yes |
| InitCoroutine | Yes |
| Insert | No |
| InsertAsync | Yes |
| InsertAwait | Yes |
| InsertInt | No |
| Int64 | No |
| Integer | Yes |
| IntegrityCk | No |
| IsNull | Yes |
| IsUnique | No |
| JournalMode | No |
| Jump | Yes |
| Last | No |
| Le | Yes |
| LoadAnalysis | No |
| Lt | Yes |
| MakeRecord | Yes |
| MaxPgcnt | No |
| MemMax | No |
| Move | No |
| Multiply | Yes |
| MustBeInt | Yes |
| Ne | Yes |
| NewRowid | Yes |
| Next | No |
| NextAsync | Yes |
| NextAwait | Yes |
| Noop | No |
| Not | Yes |
| NotExists | Yes |
| NotFound | No |
| NotNull | Yes |
| Null | Yes |
| NullRow | Yes |
| Once | No |
| OpenAutoindex | No |
| OpenEphemeral | No |
| OpenPseudo | Yes |
| OpenRead | Yes |
| OpenReadAsync | Yes |
| OpenWrite | No |
| OpenWriteAsync | Yes |
| OpenWriteAwait | Yes |
| Or | No |
| Pagecount | No |
| Param | No |
| ParseSchema | No |
| Permutation | No |
| Prev | No |
| PrevAsync | Yes |
| PrevAwait | Yes |
| Program | No |
| ReadCookie | No |
| Real | Yes |
| RealAffinity | Yes |
| Remainder | Yes |
| ResetCount | No |
| ResultRow | Yes |
| Return | Yes |
| Rewind | Yes |
| RewindAsync | Yes |
| RewindAwait | Yes |
| RowData | No |
| RowId | Yes |
| RowKey | No |
| RowSetAdd | No |
| RowSetRead | No |
| RowSetTest | No |
| Rowid | Yes |
| SCopy | No |
| Savepoint | No |
| Seek | No |
| SeekGe | Yes |
| SeekGt | Yes |
| SeekLe | No |
| SeekLt | No |
| SeekRowid | Yes |
| Sequence | No |
| SetCookie | No |
| ShiftLeft | Yes |
| ShiftRight | Yes |
| SoftNull | Yes |
| Sort | No |
| SorterCompare | No |
| SorterData | Yes |
| SorterInsert | Yes |
| SorterNext | Yes |
| SorterOpen | Yes |
| SorterSort | Yes |
| String | No |
| String8 | Yes |
| Subtract | Yes |
| TableLock | No |
| ToBlob | No |
| ToInt | No |
| ToNumeric | No |
| ToReal | No |
| ToText | No |
| Trace | No |
| Transaction | Yes |
| VBegin | No |
| VColumn | No |
| VCreate | No |
| VDestroy | No |
| VFilter | No |
| VNext | No |
| VOpen | No |
| VRename | No |
| VUpdate | No |
| Vacuum | No |
| Variable | No |
| VerifyCookie | No |
| Yield | Yes |
| ZeroOrNull | Yes |
Extensions
Limbo has in-tree extensions.
UUID
UUID's in Limbo are blobs by default.
| Function | Status | Comment |
|---|---|---|
| uuid4() | Yes | UUID version 4 |
| uuid4_str() | Yes | UUID v4 string alias gen_random_uuid() for PG compatibility |
| uuid7(X?) | Yes | UUID version 7 (optional parameter for seconds since epoch) |
| uuid7_timestamp_ms(X) | Yes | Convert a UUID v7 to milliseconds since epoch |
| uuid_str(X) | Yes | Convert a valid UUID to string |
| uuid_blob(X) | Yes | Convert a valid UUID to blob |
regexp
The regexp extension is compatible with sqlean-regexp.
| Function | Status | Comment |
|---|---|---|
| regexp(pattern, source) | Yes | |
| regexp_like(source, pattern) | Yes | |
| regexp_substr(source, pattern) | Yes | |
| regexp_capture(source, pattern[, n]) | No | |
| regexp_replace(source, pattern, replacement) | No |