TODO

Cleanup

• Schemas and attached databases: can we enhance our pragma handling from https://sqlite.org/forum/forumpost/27f85a4634
• SQLCipher: sqlite3_rekey is discouraged (https://github.com/ccgus/fmdb/issues/547#issuecomment-259219320)
• Write regression tests for #156 and #157
• deprecate ScopeAdapter(base, scopes), because base.addingScopes has a better implementation
• https://github.com/groue/GRDB.swift/issues/514
• Test NOT TESTED methods
• Get inspiration from the templates at https://github.com/woocommerce/woocommerce-ios/tree/develop/.github (https://github.com/woocommerce/woocommerce-ios/pull/3523)

Documentation

• Enhance the introduction to SQLRequest, based on the feedback in https://github.com/groue/GRDB.swift/issues/617
• Association: document how to use aggregates with inner join (testAnnotatedWithHasManyDefaultMaxJoiningRequired)
• Should we document that PRAGMA locking_mode = EXCLUSIVE improves performances? https://sqlite.org/forum/forumpost/866bf3407a

Features

• Detect when ColumnExpression.noOverwrite excludes a non-existing column. Code is in DOA.upsertStatement()`. We should not silently ignore non-existing columns, as demonstrated by https://github.com/groue/GRDB.swift/issues/1539.

• Can Swift 5.5 help us with select(.all) (request of RowDecoder), select(.id) (request of RowDecoder.ID), select(.rowid) (request of Int64)?

• Direct access to statement for bindings

• Property wrapper that decodes dictionaries (but how to tell the key column?)

• See if SQLITE_FCNTL_DATA_VERSION could help working around the lack of snapshots in order to avoid double initial fetch of ValueObservation. Result: no, it does not look it returns values that are comparable between two distinct SQLite connections (from the initial reader, and from the writer thhat starts the observation)

• Grab all FTS tokens in a string

• [NO] Can we generate EXISTS with association? Team.annotated(with: Team.players.exists) No. We already have Team.annotated(with: Team.players.isEmpty == false). It does not use an EXISTS expression, but a JOIN, and this is better for the internal consistency of the query interface, and the rules that deal with association keys.

• GRDB 6: have DatabaseRegionObservation produce DatabaseCancellable just as ValueObservation.

• RangeReplaceableCollection should have append(contentsOf: cursor)

• GRDB 6: choose persistence table

• GRDB 6: decoding errors

  • throwing FetchableRecord initializer FIRST
  • throwing Decodable FetchableRecord initializer SECOND
  • deal with as much value decoding error as possible
  • [?] expose throwing row accessors

• GRDB 6: Batch insert & Batch insert RETURNING - https://stackoverflow.com/questions/1609637/is-it-possible-to-insert-multiple-rows-at-a-time-in-an-sqlite-database

• GRDB 6: INSERT or UPDATE columns to their default value

• GRDB 6: afterNextTransactionCommit -> afterNextTransaction(onCommit:onRollback:)

• GRDB 6: encoding errors for record (EncodableRecord.encode(to:))

  • throwing EncodableRecord.encode FIRST

• [?] GRDB 6: protocol-based record container? This could avoid computing & encoding values we do not need.

• GRDB 6: encoding & statement binding errors for database values (conversion to DatabaseValue, statement binding, etc)

  • Prevent Date > 9999 from being encoded

• GRDB 6: Swift 5.7

• GRDB 6: any / some

• GRDB 6: primary associated types (cursor, requests, ...)

• GRDB 6: remove existential/generic duplicated methods

• GRDB 6: remove useless AnyXXX Type erasers

• GRDB 6: conflict resolution in persistence methods

• GRDB 6: UPSERT

• GRDB 6: support for RETURNING

  • Support for default values: Player.insert(db, as: FullPlayer.self)

• [?] GRDB 6: allow mutating update (for timestamps)

• [?] GRDB 6: let record choose persistence table (insert(into:) ?)

• [?] GRDB 6: Support opaque return types (macOS Catalina, iOS 13, tvOS 13, watchOS 6 and later: https://stackoverflow.com/questions/56518406)

• Long run edition. Use case: user edits the database (CRUD) but the application wants to commit and the end of the editing session.

  • Create an edition SQLite connection with an open transaction (a new kind of DatabaseWriter with a save() method)
  • All other writes will fail with SQLITE_BUSY. Unless they are schedules in a target dispatch queue which is paused during the edition.

• Can we use generated columns to makes it convenient to index on inserted JSON objects? https://github.com/apple/swift-package-manager/pull/3090#issuecomment-740091760

• Look at @FetchRequest: managed object context is stored in the environment, and error processing happens somewhere else (where?).

• Handle SQLITE_LIMIT_VARIABLE_NUMBER in deleteAll(_:keys:) and similar APIs. https://www.sqlite.org/limits.html

• Subqueries: request.isEmpty / [X] request.exists()

• Subqueries: request.count

• Extract one row from a hasMany association (the one with the maximum date, the one with a flag set, etc.) https://stackoverflow.com/questions/43188771/sqlite-join-query-most-recent-posts-by-each-user (failed PR: https://github.com/groue/GRDB.swift/pull/767)

• Turn a hasMany to hasOne without first/last : hasMany(Book.self).filter(Column("isBest") /* assume a single book is flagged best */).asOne()

• Support for more kinds of joins: https://github.com/groue/GRDB.swift/issues/740

• HasAndBelongsToMany: https://github.com/groue/GRDB.swift/issues/711

• Support UNION https://github.com/groue/GRDB.swift/issues/671 (https://www.sqlite.org/lang_select.html#compound)

• Measure the duration of transactions

• Improve SQL generation for Player.....fetchCount(db), especially with distinct. Try to avoid SELECT COUNT(*) FROM (SELECT DISTINCT player.* ...)

• Alternative technique for custom SQLite builds: see the Podfile at https://github.com/CocoaPods/CocoaPods/issues/9104, and https://github.com/clemensg/sqlite3pod

• Attach databases. Interesting question: what happens when one attaches a non-WAL db to a databasePool?

• SQL Generation

  • date functions
  • NOW/CURRENT_TIMESTAMP
  • ROUND() http://marc.info/?l=sqlite-users&m=130419182719263
  • RANDOM() https://www.sqlite.org/lang_corefunc.html
  • GLOB https://www.sqlite.org/lang_expr.html
  • REGEXP https://www.sqlite.org/lang_expr.html
  • CASE x WHEN w1 THEN r1 WHEN w2 THEN r2 ELSE r3 END https://www.sqlite.org/lang_expr.html

• Allow concurrent reads from a snapshot

• Check https://sqlite.org/sqlar.html

• More schema alterations

• Database.clearSchemaCache() is fine, but what about dbPool readers? Can we invalidate the cache for a whole pool?

• What can we do with cross-module-optimization? See https://github.com/apple/swift-homomorphic-encryption

• GRDB7/BREAKING: insertAndFetch, saveAndFetch, and updateAndFetch no longer return optionals (32f41472)

• GRDB7/BREAKING: AsyncValueObservation does not need any scheduler (83c0e643)

• GRDB7/BREAKING: Stop exporting SQLite (679d6463)

• GRDB7/BREAKING: Remove Configuration.defaultTransactionKind (2661ff46)

• GRDB7: Replace LockedBox with Mutex (00ccab06)

• GRDB7: Sendable: BusyCallback (e0d8e20b)

• GRDB7: Sendable: BusyMode (e0d8e20b)

• GRDB7: Sendable: TransactionClock (f7dc72a5)

• GRDB7: Sendable: Configuration (54ffb21f)

• GRDB7: Sendable: DatabaseDataEncodingStrategy (264d7fb5)

• GRDB7: Sendable: DatabaseDateEncodingStrategy (264d7fb5)

• GRDB7: Sendable: DatabaseColumnEncodingStrategy (264d7fb5)

• GRDB7: Sendable: DatabaseDataDecodingStrategy (264d7fb5)

• GRDB7: Sendable: DatabaseDateDecodingStrategy (264d7fb5)

• GRDB7: Sendable: DatabaseColumnDecodingStrategy (264d7fb5)

• GRDB7/BREAKING: Remove DatabaseFuture and concurrentRead (05f7d3c8)

• GRDB7: Sendable: DatabaseFunction (6e691fe7)

• GRDB7: Sendable: DatabaseMigrator (22114ad4)

• GRDB7: Not Sendable: FilterCursor (b26e9709)

• GRDB7: Sendable: RowAdapter (d138af26)

• GRDB7: Sendable: ValueObservationScheduler (8429eb68)

• GRDB7: Sendable: DatabaseCollation (4d9d67dd)

• GRDB7: Sendable: LogErrorFunction (f362518d)

• GRDB7: Sendable: ReadWriteBox (57a86a0e)

• GRDB7: Sendable: Pool (f13b2d2e)

• GRDB7: Sendable: OnDemandFuture fulfill (2aabc4c1)

• GRDB7: Sendable: WALSnapshotTransaction (7fd34012)

• [-] GRDB7: sending closures for SerializedDatabase

• [-] GRDB7: sending closures for ValueObservationScheduler

• GRDB7: Sendable closures for ValueObservation.handleEvents

• GRDB7: Not Sendable: Record (make it explicit if subclasses can be made sendable)

• GRDB7: Not Sendable: databasepublishers/databaseregion, migrate, read, value, write

• GRDB7: Sendable closures for writePublisher

• GRDB7: Sendable closures for readPublisher

• [-] GRDB7: Not Sendable: fts5customtokenizer, fts5tokenizer, fts5wrappertokenizer

• GRDB7: Sendable: DatabasePromise (05899228, 5a2c15b8)

• GRDB7: Sendable: TableAlias (f2b0b186)

• GRDB7: Sendable: SQLRelation (9545bf70)

• GRDB7: Sendable: SQL (ac33856f)

• GRDB7: Split Row.swift (2ce8a619)

• GRDB7: Cleanup ValueReducer (6c73b1c5)

• GRDB7: DatabaseCursor has a primary associated type (b11c5dd2)

• GRDB7: Enable Strict Concurrency Checks (6aa43ded)

• GRDB7: Sendable: OrderedDictionary (e022c35b)

• GRDB7: Rename ReadWriteBox to ReadWriteLock (7f5205ef)

• GRDB7: Sendable: DatabaseRegionConvertible (b4677ded)

• GRDB7: Sendable: ValueConcurrentObserver (87b9db65, 5465d056)

• GRDB7: Sendable: ValueWriteOnlyObserver (ff2a7548)

• GRDB7: Sendable: DatabaseCancellable (2f93f00b, 8f486a5e)

• GRDB7: ValueObservation closures

• [?] GRDB7: DatabasePublishers.ValueSubscription

• GRDB7: Sendable: ValueObservation (93f6f982)

• [?] GRDB7: Not Sendable: SharedValueObservation

• GRDB7: doc (c0838cf9)

• GRDB7/BREAKING: PersistenceContainer is Sendable (50eefa8c)

• GRDB7: TableRecord.databaseSelection must be declared as a computed property (24d232aa)

  • Doc
  • Migration Guide

• GRDB7: Sendable: Association (b06aaee4)

• GRDB7/Tests: Sendable: ValueObservationRecorder (2947b3d7)

• GRDB7: ValueObservation.print cautiously uses its stream argument (5f8b39b7)

• GRDB7/Tests: use a single and Sendable test TextOutputStream (bbb1a736)

• GRDB7: ValueObservation needs a ValueReducer, not a _ValueReducer (08733108)

• GRDB7: Database support for cancellation (4ddf4bca)

• GRDB7: SerializedDatabase support for async db access with support for Task cancellation (737cb149)

• GRDB7: DatabaseWriter async methods support Task cancellation (a5226501)

• GRDB7: DatabaseReader async methods support Task cancellation (10c9d311)

• GRDB7: Document that async methods can throw CancellationError (8df18fb8)

• [-] GRDB7: Sendable: AssociationAggregate (48ad10ae)

• GRDB7: Sendable: AsyncValueObservation (necessary for async algorithm) (ce63cdfa)

• GRDB7: Sendable: DatabaseRegionObservation (b4ff52fb)

• [-] GRDB7: DispatchQueue.asyncSending (7b075e6b)

• GRDB7: Replace sequences with collection (e.g. https://github.com/tidal-music/tidal-sdk-ios/pull/39)

• GRDB7: Replace some DatabaseReader/Writer with any where possible, in order to avoid issues with accessing DatabaseContext from GRDBQuery (if the problem exists in Xcode 16)

• GRDB7: bump to iOS 13, macOS 10.15, tvOS 13 (for ValueObservation support for MainActor)

• GRDB7: DatabasePublishers.Value should carry the type of the Scheduler, so that we can rely on main-actor-isolated callbacks.

• GRDB7: Remove warning about "products" in Package.swift

• GRDB7: Fixits

  • defaultTransactionKind
  • concurrentRead

• GRDB7: Swift Concurrency recommendations

  • Record classe(s)
  • InferSendableFromCaptures

• GRDB7: stop fostering the Record class

  • Remove all mentions from the README
  • Warn about it in the documentation of the class.

• GRDB7: Breaking changes documentation

  • [BREAKING] Xcode 16+, Swift 6+
  • [BREAKING] iOS 13+
  • [BREAKING] macOS 10.15+
  • [BREAKING] tvOS 13+
  • [BREAKING] watchOS 7+
  • [-] insertAndFetch, updateAndFetch, saveAndFetch
  • CSQLite renamed to GRDBCSQLite
  • CSQLite is not exported
  • defaultTransactionKind
  • concurrentRead
  • record column strategies:
    • databaseDataEncodingStrategy
    • databaseDateEncodingStrategy
    • databaseUUIDEncodingStrategy
    • databaseDataDecodingStrategy
    • databaseDateDecodingStrategy
  • PersistenceContainer subscript no longer returns its input value
  • cancellation of async database access
  • Async sequences built from ValueObservation schedule values and errors on the cooperative thread pool by default.
  • TableRecord.databaseSelection should be declared as a computed static property
  • [-] databaseDecodingUserInfo and databaseEncodingUserInfo must be declared as a computed property

• GRDB7: Review experimental apis

• [?] GRDB7: Change ValueObservation callback argument so that it could expose snapshots? https://github.com/groue/GRDB.swift/discussions/1523#discussioncomment-9092500

Unsure if necessary

• Have TableAlias embed the record type
• Have SQLPrimaryKeyExpression embed the record type
• Remove support for suspended databases - https://inessential.com/2020/02/13/how_we_fixed_the_dreaded_0xdead10cc_cras
• https://sqlite.org/pragma.html#pragma_index_xinfo
• filter(rowid:), filter(rowids:)
• https://github.com/apple/swift-evolution/blob/master/proposals/0075-import-test.md
• https://forums.swift.org/t/how-to-encode-objects-of-unknown-type/12253/6
• Configuration.crashOnError = true
• Glossary (Database Access Methods, etc.)
• Not sure: type safety for SQL expressions
  • Introduce some record protocol with an associated primary key type. Restrict filter(key:) methods to this type. Allow distinguishing FooId from BarId types.
  • Replace Column with TypedColumn. How to avoid code duplication (repeated types)? Keypaths?
• Remove prefix from association keys when association name is namespaced: https://github.com/groue/GRDB.swift/issues/584#issuecomment-517658122
• Alternative support for custom SQLite builds, with CocoaPods: https://github.com/CocoaPods/CocoaPods/issues/9103

Unsure how

• Association limits: Author.including(optional: Author.books.order(date.desc).first)

• Joins and full-text tables

• UPSERT https://www.sqlite.org/lang_UPSERT.html

• Support for "INSERT INTO ... SELECT ...".

• Look at the jazzy configuration of https://github.com/bignerdranch/Deferred

• Predicates, so that a filter can be evaluated both on the database, and on a record instance.

  After investigation, we can't do it reliably without knowing the collation used by a column. And SQLite does not provide this information elsewhere than in the full CREATE TABLE statement stored in sqlite_master.

• ValueObservation erasure

  Copy

  // Do better than this
  observation.mapReducer { _, reducer in AnyValueReducer(reducer) }
  

• new.updateChanges(from: old) vs. old.updateChanges(with: { old.a = new.a }). This is confusing.

Reading list

• Documentation generation: https://twitter.com/jckarter/status/987525569196650496: cmark is the implementation the Swift compiler uses for doc comments etc.
• VACUUM (https://blogs.gnome.org/jnelson/)
• http://www.sqlite.org/intern-v-extern-blob.html
• https://sqlite.org/sharedcache.html
• Undo: https://www.sqlite.org/undoredo.html
• Undo: https://sqlite.org/sessionintro.html
• Swift, Xcode:List of Swift documentation keywords: https://swift.org/documentation/api-design-guidelines.html#special-instructions
• Swift, Xcode:Amazing tip from Xcode labs: add a EXCLUDED_SOURCE_FILE_NAMES build setting to conditionally exclude sources for different configuration: https://twitter.com/zats/status/74386298602026496
• SQLITE_ENABLE_SQLLOG: http://mjtsai.com/blog/2016/07/19/sqlite_enable_sqllog/
• Swift, Xcode: https://github.com/apple/swift/blob/master/docs/OptimizationTips.rst
• Associations: http://docs.diesel.rs/diesel/associations/index.html
• FTS: http://cocoamine.net/blog/2015/09/07/contentless-fts4-for-large-immutable-documents/
• pinyin: http://hustlzp.com/post/2016/02/ios-full-text-search-using-sqlite-fts4
• Realm oddity: http://stackoverflow.com/questions/41721769/realm-update-object-without-updating-lists
• File protection: https://github.com/ccgus/fmdb/issues/262
• File protection: https://lists.apple.com/archives/cocoa-dev/2012/Aug/msg00527.html
• iOS apps are terminated every time they enter the background if they share an encrypted database with an app extension
• Cross-Process notifications with CFNotificationCenterGetDarwinNotifyCenter