Fixed

• Reverted a fix from the 2.0.1 release that breaks valid INSERT … ON CONFLICT queries

This is a bugfix release containing the following fixes:

• Fixed an issue with diesel_cli generating incompatible type names for the generate_missing_sql_type_definitions feature on PostgreSQL
• Fixed an issue how diesel_cli handles sqlite urls while checking if a given database exists
• Fixed an issue with PgConnection becoming unusable after hitting a database error in certain situations
• Fixed an issue with diesel generating invalid SQL for certain INSERT … ON CONFLICT queries
• Fixed diesel_derives generating code that triggers the disabled by default unused_qualifications lint

This release includes updated versions of diesel, diesel_cli and diesel_derives

Diesel 2.0.0 contains the contributions of more than 130 people. More than 1700 commits were submitted over a span of 3 years.

As part of this release we introduced numerous new features and rewrote large parts of the internal structure. Check out our changelog for a complete list of changes. As this is a new major Diesel release it contains a number of breaking changes. Checkout our migration guide for details about how to handle those breaking changes.

This release contains the following parts:

• diesel 2.0.0-rc.0
• diesel_derives 2.0.0-rc.0
• diesel_migrations 2.0.0-rc.0
• diesel_cli 2.0.0-rc.0
• diesel_dynamic_schema 0.2.0-rc.0

This release marks a first prerelease of the upcoming Diesel 2.0 release. We ask you for your help to finalise the release. Checkout the "Timeline for a Diesel 2.0 release" section for details about how you can help us finishing the release.

Features

As a highlight Diesel 2.0.0 adds support for the following features:

• Fully type checked GROUP BY support
• Support for table aliasing
• Support for defining select clauses via a corresponding type
• Support for UNION/INTERSECT queries

Support for GROUP BY clauses

Diesel 2.0 adds support for GROUP BY clauses for select queries.

This means queries like the following one will just work.

 users::table.inner_join(posts::table)
    .group_by(users::id)
    .select((users::name, count(posts::id)))

As this is the case for all other Diesel built-in query dsl, this construct is fully checked at compile time. This means Diesel will ensure that the GROUP BY clause is valid for the current query and it will also ensure that expressions appearing inside of your SELECT clause will match the aggregation rules provided by the current GROUP BY clause.

Support for table aliasing

Diesel 2.0 adds support for table aliasing. This enables users to write queries, where a table appears more than once in the corresponding FROM clause. For this Diesel provides a Diesel::alias! macro that allows to define new alias for existing tables.

The following query demonstrates the support for this feature:

// Define new table alias for the existing `users` table
let users1 = diesel::alias!(schema::users as user1);

// Use the corresponding alias inside any existing query
users::table
    .inner_join(users1.on(users::id).eq(users1.field(users::id))))
    .select((users::id, users::name, users1.field(users::name)))
    .order_by(users1.field(users::id))

Again all of this is checked at compile time. So similar to a normal table, columns from aliases are only allowed to appear if the corresponding query actually uses the alias.

Implied selection via the new Selectable trait

Diesel 2.0 features a new Selectable trait and derive that lets users declare that a type expects a certain kind of select clause. The major use case for this feature is to ensure that columns from a specific query are always requested in the right order for a corresponding type implementing Queryable. This also works for complex queries involving joins or other kinds of nesting.

#[derive(Queryable, Selectable)]
struct User {
    id: i32,
    name: String,
}

let first_user = users.select(User::as_select()).first(connection)?;

Diesel enforces at type system level that once you provided such a select clause via User::as_select() you are only allowed to construct this type from the returned result of the corresponding query. This means there is no need to specify the User type twice in the query above.

Support for UNION/INTERSECT/EXCEPT queries

Diesel 2.0 extents the query builder to support query combinations via UNION/INTERSECT/EXCEPT. This allows you to easily chain multiple queries together as long as they return fields of the same type. Queries like the following one are now supported:

 users.select(user_name.nullable())
    .union(animals.select(animal_name).filter(animal_name.is_not_null()))

As always this is checked at compile time to reject invalid queries, like for example that ones containing select clauses with different fields.

Call for Participation

The release of Diesel 2.0 does not only include the features listed above, but also marks the point where the following things can be provided by third party crates:

• Custom QueryDsl extensions to support previously unsupported SQL features. Checkout diesel_full_text_search for an example
• Alternative query dsl implementations reusing the existing Connection infrastructure
• Custom Connection implementations for existing backends
• Custom Connection and Backend implementations for previously unsupported backends. Checkout diesel-oci for an example.

We encourage our community to try out those features. Especially we would like to see experimentation around:

• Previously unsupported database backends
• Pure rust implementations of existing backend implementations. Checkout this and this discussion for starting points.
• Alternative query dsl implementations. Checkout this discussion as starting point.

Please get in touch with us for pointers, help and details.

Input for Future Roadmap

With the release of Diesel 2.0 the planing for our next releases start. Hopefully they will not take as long as Diesel 2.0. We are looking for input on which features are wanted by our community. Please open a discussion thread with your idea in our discussion forum.

Weiznich will work on improving error messages for trait heavy crates based on a Rust Foundation Project Grant. This work will hopefully improve error messages for Diesel as well. If you are aware of bad error messages please submit a minimal example here.

Thanks

As part of this release we would like to welcome @Ten0 as part of the diesel core team.

Thank you to everyone who helped make this release happen through bug reports, and discussion on Gitter. While we don't have a way to collect stats on that form of contribution, it's greatly appreciated.

In addition to the Diesel core team, 141 people contributed code to this release. A huge thank you to:

• Alessandro Menezes
• Alexander 'z33ky' Hirsch
• Alexei Pastuchov
• Alice Ryhl
• Amila Welihinda
• Andre Braga Reis
• Andreas Runfalk
• Andrew Safigan
• Andrew Speed
• Andy Russell
• Artem Vorotnikov
• Arve Seljebu
• Billy Chan
• Blas Rodriguez Irizar
• Bryan Henry
• Callym
• Caroline Glassberg-Powell
• Cassie Jones
• Chenxi Yuan
• Chris Eckhardt
• Chris Hanks
• Chris Maddox
• Chris West (Faux)
• Clouds Flowing
• Corentin Henry
• Daniel Buse
• Danilo Bargen
• David Teller
• David Tulig
• DebugSteven
• Diggory Blake
• Dmitriy Pleshevskiy
• Dusty Mabe
• DrVilepis
• EclipsedSolari
• Emile Fugulin
• Emm
• Emmanuel Surleau
• Erlend Langseth
• Felix Watts
• Filip Gospodinov
• Garrett Thornburg
• Giorgio Gambino
• Grégory Obanos
• Hal Gentz
• Han Xu
• Heliozoa
• Henk van der Laan
• Henry Boisdequin
• Hirokazu Hata
• Iban Eguia (Razican)
• Igor Raits
• Ivan Tham
• JR Heard
• Jean SIMARD
• Jeremy Stucki
• Jiří Sejkora
• jigaoqiang
• Joel Parker Henderson
• John Brandt
• Jonas Platte
• Jonas Schievink
• Joshua Koudys
• Juhasz Sandor
• Justice4Joffrey
• Katharina Fey
• Kevin King
• Kevin Kirchner
• Khionu Sybiern
• Kitsu
• Koisell
• Kononnable
• Leonardo Yvens
• Lukas Markeffsky
• Maccesch
• Marc-Stefan Cassola
• Martell Malone
• Martijn Groeneveldt
• Martin Nordholts
• Matthew Kuo
• Matthieu Guillemot
• Mcat12
• Meven
• Mike Cronce
• Mr Ceperka
• Nafiul Islam
• Nathan Papapietro
• Nicholas Yang
• Oliver Cooper
• Otto Castle
• Pankaj Jangid
• Paolo Barbolini
• Paul Le Corre
• Paul Martensen
• Pavan Kumar Sunkara
• Paweł Przeniczny
• Philip Trauner
• Raphael Arias
• Roman
• Ryan Leckey
• Sarthak Singh
• Scott Driggers
• Sean Klein
• Simon Ertl
• Spencer Taylor
• Steven Chu
• Storm Timmermans
• Sébastien Santoro
• Takayuki Maeda
• Thomas Constantine Moore
• Thomas Eizinger
• Thomas Etter
• Tom MacWright
• Tuetuopay
• Urhengulas
• Vanio Begic
• WebeWizard
• William Myers
• Yin Jifeng
• Yuki Okushi
• Zane Duffield
• blackghost1987
• czotomo
• dchenk
• ejc Drobnič
• gorbit99
• hasezoey
• hi-rustin
• kevinpoitra
• kpcyrd
• matthew-dowdell
• ode79
• ropottnik
• telios
• theredfish
• zoewithabang
• Zhenhui Xie
• Émile Fugulin
• κeen
• 二手掉包工程师
• 棒棒彬_Binboy

We are happy to announce the release of Diesel 2.0.0 RC1

This release contains a number of fixes and improvements compared to the previous 2.0.0 RC0 release.

Notably the following fixes and improvements are included:

• A fix for an issue preventing connection reuse with the built-in r2d2 integration
• Support for types from the ipnet crate
• Support for loading values via libpq's row by row mode
• Improvements to error messages generated by #[derive(Insertable)] for the case of type mismatches

This release hopefully marks the last prerelease before a stable 2.0.0 release. We plan to release the final 2.0.0 soon after this, as long no other blocking issues are found.

Thank you to everyone who helped make this release happen through bug reports, and discussion on Gitter. While we don't have a way to collect stats on that form of contribution, it's greatly appreciated.

In addition to the Diesel core team, 8 people contributed code to this release. A huge thank you to:

• Chris Eckhardt
• Emile Fugulin
• Iban Eguia Moraza
• Jean SIMARD
• Martin Nordholts
• Otto Castle
• Sean Klein
• Steven Chu

Diesel 2.0.0-rc.0

This release marks the first release candidate for the upcoming Diesel 2.0 Release.

Diesel 2.0.0 contains the contributions of more than 130 people. More than 1700 commits were submitted over a span of 3 years.

As part of this release we introduced numerous new features and rewrote large parts of the internal structure. Check out our changelog for a complete list of changes. As this is a new major Diesel release it contains a number of breaking changes. Checkout our draft migration guide for details about how to handle those breaking changes.

This release contains the following parts:

• diesel 2.0.0-rc.0
• diesel_derives 2.0.0-rc.0
• diesel_migrations 2.0.0-rc.0
• diesel_cli 2.0.0-rc.0
• diesel_dynamic_schema 0.2.0-rc.0

This release marks a first prerelease of the upcoming Diesel 2.0 release. We ask you for your help to finalise the release. Checkout the "Timeline for a Diesel 2.0 release" section for details about how you can help us finishing the release.

Features

As a highlight Diesel 2.0.0 adds support for the following features:

• Fully type checked GROUP BY support
• Support for table aliasing
• Support for defining select clauses via a corresponding type
• Support for UNION/INTERSECT queries

Support for GROUP BY clauses

Diesel 2.0 adds support for GROUP BY clauses for select queries.

This means queries like the following one will just work.

 users::table.inner_join(posts::table)
    .group_by(users::id)
    .select((users::name, count(posts::id)))

As this is the case for all other Diesel built-in query dsl, this construct is fully checked at compile time. This means Diesel will ensure that the GROUP BY clause is valid for the current query and it will also ensure that expressions appearing inside of your SELECT clause will match the aggregation rules provided by the current GROUP BY clause.

Support for table aliasing

Diesel 2.0 adds support for table aliasing. This enables users to write queries, where a table appears more than once in the corresponding FROM clause. For this Diesel provides a Diesel::alias! macro that allows to define new alias for existing tables.

The following query demonstrates the support for this feature:

// Define new table alias for the existing `users` table
let users1 = diesel::alias!(schema::users as user1);

// Use the corresponding alias inside any existing query
users::table
    .inner_join(users1.on(users::id).eq(users1.field(users::id))))
    .select((users::id, users::name, users1.field(users::name)))
    .order_by(users1.field(users::id))

Again all of this is checked at compile time. So similar to a normal table, columns from aliases are only allowed to appear if the corresponding query actually uses the alias.

Implied selection via the new Selectable trait

Diesel 2.0 features a new Selectable trait and derive that lets users declare that a type expects a certain kind of select clause. The major use case for this feature is to ensure that columns from a specific query are always requested in the right order for a corresponding type implementing Queryable. This also works for complex queries involving joins or other kinds of nesting.

#[derive(Queryable, Selectable)]
struct User {
    id: i32,
    name: String,
}

let first_user = users.select(User::as_select()).first(connection)?;

Diesel enforces at type system level that once you provided such a select clause via User::as_select() you are only allowed to construct this type from the returned result of the corresponding query. This means there is no need to specify the User type twice in the query above.

Support for UNION/INTERSECT/EXCEPT queries

Diesel 2.0 extents the query builder to support query combinations via UNION/INTERSECT/EXCEPT. This allows you to easily chain multiple queries together as long as they return fields of the same type. Queries like the following one are now supported:

 users.select(user_name.nullable())
    .union(animals.select(animal_name).filter(animal_name.is_not_null()))

As always this is checked at compile time to reject invalid queries, like for example that ones containing select clauses with different fields.

Timeline for Diesel 2.0

We consider this release candidate of Diesel 2.0 as feature complete. Before finally releasing a stable 2.0 release we want to address the following points:

• Updating the guides on our web page to use the new Diesel 2.0 release
• Improve the migration guide to cover missed details or changes
• Improve our documentation to include more details on new features

You can help us rounding up this release by:

• Updating your code to the RC release and report problems here
• Help us improving the documentation by submitting reports and improvements
• Help us porting our guides to the new release by submitting a PR here

Thanks

As part of this release we would like to welcome @Ten0 as part of the diesel core team.

Thank you to everyone who helped make this release happen through bug reports, and discussion on Gitter. While we don't have a way to collect stats on that form of contribution, it's greatly appreciated.

In addition to the Diesel core team, 134 people contributed code to this release. A huge thank you to:

• Alessandro Menezes
• Alexander 'z33ky' Hirsch
• Alexei Pastuchov
• Alice Ryhl
• Amila Welihinda
• Andre Braga Reis
• Andreas Runfalk
• Andrew Safigan
• Andrew Speed
• Andy Russell
• Artem Vorotnikov
• Arve Seljebu
• Billy Chan
• Blas Rodriguez Irizar
• Bryan Henry
• Callym
• Caroline Glassberg-Powell
• Cassie Jones
• Chenxi Yuan
• Chris Hanks
• Chris Maddox
• Chris West (Faux)
• Clouds Flowing
• Corentin Henry
• Daniel Buse
• Danilo Bargen
• David Teller
• David Tulig
• DebugSteven
• Diggory Blake
• Dmitriy Pleshevskiy
• Dusty Mabe
• EclipsedSolari
• Emile Fugulin
• Emm
• Emmanuel Surleau
• Erlend Langseth
• Felix Watts
• Filip Gospodinov
• Garrett Thornburg
• Giorgio Gambino
• Grégory Obanos
• Hal Gentz
• Han Xu
• Henk van der Laan
• Henry Boisdequin
• Hirokazu Hata
• Iban Eguia (Razican)
• Igor Raits
• Ivan Tham
• JR Heard
• Jeremy Stucki
• Jiří Sejkora
• Joel Parker Henderson
• John Brandt
• Jonas Platte
• Jonas Schievink
• Joshua Koudys
• Juhasz Sandor
• Justice4Joffrey
• Katharina Fey
• Kevin King
• Kevin Kirchner
• Khionu Sybiern
• Kitsu
• Koisell
• Kononnable
• Leonardo Yvens
• Lukas Markeffsky
• Maccesch
• Marc-Stefan Cassola
• Martell Malone
• Martijn Groeneveldt
• Matthew Kuo
• Matthieu Guillemot
• Mcat12
• Meven
• Mike Cronce
• Mr Ceperka
• Nafiul Islam
• Nathan Papapietro
• Nicholas Yang
• Oliver Cooper
• Otto Castle
• Pankaj Jangid
• Paolo Barbolini
• Paul Le Corre
• Paul Martensen
• Pavan Kumar Sunkara
• Paweł Przeniczny
• Philip Trauner
• Raphael Arias
• Roman
• Ryan Leckey
• Sarthak Singh
• Scott Driggers
• Sean Klein
• Simon Ertl
• Spencer Taylor
• Steven Chu
• Storm Timmermans
• Sébastien Santoro
• Takayuki Maeda
• Thomas Constantine Moore
• Thomas Eizinger
• Thomas Etter
• Tom MacWright
• Tuetuopay
• Urhengulas
• Vanio Begic
• WebeWizard
• William Myers
• Yin Jifeng
• Yuki Okushi
• Zane Duffield
• blackghost1987
• czotomo
• dchenk
• ejc Drobnič
• gorbit99
• hasezoey
• hi-rustin
• kevinpoitra
• kpcyrd
• matthew-dowdell
• ode79
• ropottnik
• telios
• theredfish
• zoewithabang
• Émile Fugulin
• κeen
• 二手掉包工程师
• 棒棒彬_Binboy

This release fixes an incompatibility between features passed to diesel and diesel_migrations while using cargos new resolver feature (resolver = "2") which will become the new default with the upcoming Rust 2021 edition

• Updated libsqlite3-sys to allow version 0.22
• Updated ipnetwork to allow version 0.18

Fixed

• Fixed a use-after-free issue in the QueryableByName implementation of our Sqlite backend
• Updated several dependencies

Fixed

• Update several dependencies
• Fixed an issue where transactions that would fail to commit would leave the connection in a broken non-committed non-rolled-back state.
• Fix a bug that result in leaking sockets/file descriptors on failed connection attempts for postgresql
• Fix an incompatibility with newer libmysqlclient versions
• Remove some potential harmful usages of mem::uninitialized

Fixed

• Update several dependencies
• Fixed a bug with printing embedded migrations

As part of this release also updated versions of migration_internals and migration_macros are published.

Fixed

• Updated several dependencies
• Fixed an issue where the postgresql backend exploits implementation defined behaviour
• Fixed issue where rustdoc failed to build the documentation
• diesel_derives and diesel_migrations are updated to syn 1.0

New Features

In contrast to the last release most changes in this release are minor or internal. We've added support for newer versions of some dependency crates (libsqlite-sys, uuid, ipnetwork).

Diesel CLI got a command line flag to check if a generated schema matches the already existing one. This is useful for CI setups to check there if the committed generated schema file matches the committed migrations.

We've added support for the diesel_mange_updated_at('table_name') SQL function on SQLite. This function handles the setup of an trigger that automatically updates the updated_at column on update operations.

Additionally several helpers were added to support the deserialisation of tuples and composite types on PostgreSQL.

As always, a full list of changes can be found it in the changelog

Thanks

Thank you to everyone who helped make this release happen through bug reports, and discussion on Gitter. While we don't have a way to collect stats on that form of contribution, it's greatly appreciated.

In addition to the Diesel core team, 29 people contributed code to this release. A huge thank you to:

• Aleksey Ivanov
• Andrew Speed
• Carlos Diaz-Padron
• Daniel Silverstone
• Dirkjan Ochtman
• Dominik Sander
• Eyal Kalderon
• Galuh Sahid
• Hirokazu Hata
• Jake Goulding
• Jo Liss
• Josh Leeb-du Toit
• Kevin Stenerson
• kpcyrd
• Marcus Stollsteimer
• Matej Stuchlik
• Nikita Sivakov
• notryanb
• Rasmus Kaj
• Richard Petrie
• Rotem Yaari
• Ryan Leckey
• Sergio Benitez
• Simon Heath
• Stephen Muss
• Trinh Hoang Anh

This is a small bugfix release, addressing an issue with MySQL 8.0. The behavior of the C API in libmysqlclient changed in this version of MySQL, causing problems when a connection pool was used with Diesel.

If you are not using MySQL, or are on a version older than 8.0, this release does not affect you.

This release contains two major bugfixes. This release fixes the behavior of unsigned types on MySQL, and a compile time issue caused by the use of #[sql_name] in sql_function! with no return type. This release only affects users who are using unsigned types on MySQL, or who had code which failed to compile with 1.3.1.

New Features

This release includes a couple of major changes to how Diesel projects are developed. In the past, we've had 2 ways to generate schema.rs. A procedural macro called infer_schema!, and a CLI command diesel print-schema. We've recommended using the CLI command for a long time, but infer_schema! was still useful for early prototypes.

At the beginning of a project, your database schema changes much more frequently. It's extremely annoying to have to remember to run a second command after running your migrations.

Diesel CLI 1.3 now supports a configuration file to customize its behavior. One of the new capabilities this provides is the ability to automatically regenerate schema.rs whenever you run or revert a migration. This means you no longer have to remember to run diesel print-schema when things change.

Because of this, we are deprecating diesel_infer_schema. 1.3 will be the final release of that crate. However, diesel_infer_schema 1.3 will continue to work with diesel until at least Diesel 2.0. You can see all of the capabilities of the new configuration file at http://diesel.rs/guides/configuring-diesel-cli.

This release also includes a complete redesign of the sql_function! macro. The new syntax is significantly closer to normal Rust. For example, what used to be written as:

sql_function! {
    lower, lower_t, (x: Text) -> Text,
    "Here are the docs for `lower`
It's awkward to make multiline"
}

Can now be written as:

sql_function! {
    /// Here are the docs for `lower`
    /// It's just a normal doc comment.
    fn lower(x: Text) -> Text;
}

The new form also supports much more than the old one, including aggregate functions, function renaming, and generic functions. Things like MAX could previously not be expressed with sql_function!. However, now the definition looks like this:

sql_function! {
    #[aggregate]
    fn max<ST: SqlOrd + IntoNullable>(expr: ST) -> ST::Nullable;
}

Finally, the redesigned sql_function! supports user defined functions on SQLite. SQLite differs from other databases, in that custom functions aren't defined in SQL. Instead you give it a C function pointer to use for the body. With Diesel, you can just give us any Rust closure that takes appropriate argument types, and we'll handle gluing that to SQLite for you.

You can find examples for all of this in the docs for sql_function!.

In addition to the headline features, this release includes a ton of quality of life changes including expanded support for locking clauses, more global support for mathematic operators, and more. As always, for a full list of changes you can find it in [the changelog].
[the changelog]: https://github.com/diesel-rs/diesel/blob/v1.3.0/CHANGELOG.md

Thanks

Thank you to everyone who helped make this release happen through bug reports, and discussion on Gitter. While we don't have a way to collect stats on that form of contribution, it's greatly appreciated.

In addition to the Diesel core team, 12 people contributed code to this release. A huge thank you to:

• Aleksey Ivanov
• Christopher Brickley
• David Reid
• Diggory Blake
• Graham Turner
• Katharina
• Matt Kraai
• Nick Babcock
• Richard Petrie
• Simon Dickson
• Sunrin SHIMURA
• Thierry Berger

This release contains several long awaited features.

We've re-introduced the ability to use bind params with the sql function, in a way which is harder to mis-use. This functionality was present prior to 1.0, but was removed when sql_function was added over concerns about its use with the rest of the query builder. Recent developments have proved those concerns to be valid, but this new API fills that niche. Thanks to @notryanb for taking the lead on this feature.

We've also added the ability to insert from a select statement (e.g. queries in the form of INSERT INTO table (...) SELECT .... This is a feature request that has come up repeatedly since release, and we're happy to finally bring it to you. We've also added alternate forms of our insert API which feel better when used with select statements. You can find the full details in the CHANGELOG.

Finally, we've rewritten our custom dervies from scratch to take advantage of new diagnostic tools in recent versions of nightly Rust. If you turn on the unstable feature of Diesel on a nightly compiler, you'll find that you get dramatically improved error messages from our derives. For the best error messages, you should also set RUSTFLAGS="--cfg procmacro2_semver_exempt".

Additionally, as of this release, Diesel is now powered by the blockchain. Because it's 2018 and that's how it works now I guess. See the CHANGELOG for full details.

In addition to the headline features, there were a ton of features that we don't have time to mention here. As always, for a full list of changes you can find a full list in the CHANGELOG.

Thanks

Thank you to everyone who helped make this release happen through bug reports, and discussion on Gitter. While we don't have a way to collect stats on that form of contribution...

In addition to the Diesel core team, 14 people contributed code to this release. A huge thank you to:

• Alex Kitchens
• Andrew Weiss
• Arun Kulshreshtha
• Brandur
• EloD10
• Jacob Chae
• Jordan Petridis
• Josh Leeb-du Toit
• Kerollmops
• Mathias Svensson
• Ryan Blecher
• Sander Maijers
• Seth Larson
• YetAnotherMinion

This release fixes a minor issue with our r2d2 support. In 1.1 we recommend that people access r2d2 via diesel::r2d2. However, r2d2 has a type called Error, which was shadowed by our own type called Error in that same module, making it inaccessible. This release adds an alias PoolError to point at r2d2::Error.

Thanks to YetAnotherMinion for working on this release.

Improved Support for Adding New Types

The primary focus of this release was improving the ergonomics of adding support for new types in Diesel.

For implementing new SQL types, we've added #[derive(SqlType)] which implements many traits that you need to implement for every SQL type. See the documentation for HasSqlType for details on this derive.

For implementing new mappings, we've added #[derive(FromSqlRow)] and #[derive(AsExpression)]. These derives will replace the majority of the boilerplate that was previously required when supporting new types. Adding support for new types in Diesel 1.1 should only require implementing FromSql and ToSql. The derives will handle the rest.

We've also provided FromSql impls for *const str and *const [u8]. Due to the design of FromSql, we can't provide impls for &str and &[u8] without a breaking change. However many impls just need to parse a string or some bytes, and don't need the allocation that would come from String or Vec<u8>. This will require unsafe code to use, but should make certain implementations more efficient.

Finally, we've restructured how our serialize/deserialize modules are structured, and provided type aliases to make implementations of FromSql and ToSql more consise.

r2d2_diesel is Now Part of Diesel

Finally, this release merges r2d2_diesel into Diesel itself. The main benefit of doing this is that we can implement Connection for PooledConnection, removing the need for explicit &* when using r2d2. This should also help to prevent version mismatches when changing Diesel versions.

To use the new r2d2 support, remove r2d2 and r2d2_diesel from your Cargo.toml. Add the r2d2 to your enabled features on diesel. Replace extern crate r2d2 with pub use diesel::r2d2. Replace any r2d2_diesel:: with diesel::r2d2::.

Thanks

In addition to the headline features, there were dozens of smaller additions which should make using Diesel even better! As always, you can check the CHANGELOG for a full list of changes in this release.

In addition to the Diesel core team, 8 people contributed to this release. A huge thank you to:

• Ashe Connor
• Chris Pick
• Evan
• Georg Semmler
• MarcManiez
• Martin Lindhe
• Oliver Schneider
• Ryan Blecher

We didn't quite make it for 2017, but Diesel 1.0 is finally here! There are no changes between Diesel 1.0 and 1.0.0-rc1.

1.0.0 marks stability for Diesel. While there are many more features that will be added in the future, there will be no breaking changes from this point forward without a major version bump (which we do not anticipate happening for many years).

A lot has happened since Diesel 0.1 was released over 2 years ago. While it would be impossible to list every major change that has happened since then, here are a few highlights:

• Expanded from a PostgreSQL specific library to supporting SQLite and MySQL
• Went from nightly-only to nightly-optional to working purely on stable Rust
• diesel print-schema replaced infer_schema! as the go-to way to infer your database schema.
• Added support for a significant portion of SQL queries which could not be represented in 0.1

It's been a great honor to watch this community grow and thrive as this library has developed. I look forward to continuing to evolve Diesel, and seeing how far it can go.

In addition to the Diesel core team, 98 people have contributed to Diesel. A huge thank you to everyone who made this and every prior release possible:

• Adam Perry
• Adrian Perez de Castro
• Alex Alvarez
• Alex Kitchens
• Alexey Zabelin
• Andrew Lazarus
• Andrew Ryan Lazarus
• Arnar Mar Sig
• Barosl Lee
• Blake Pettersson
• Bob
• Boris-Chengbiao Zhou
• Brandon W Maister
• Cameron Alexander
• Cengiz Can
• Christopher Brickley
• Cyryl Płotnicki
• Daniel Durante
• Danilo Bargen
• David Szotten
• Derek Prior
• Dimiter Petrov
• Dorian Scheidt
• Enether
• Eric Kidd
• Erich Cordoba
• FliegendeWurst
• Flux Xu
• Garrett Squire
• Georg Semmler
• Graham Grochowski
• JD Gonzales
• Jake Goulding
• Jakob Gillich
• James Kominick
• Jethro Beekman
• Jim McGrath
• Jimmy Cuadra
• John Gallagher
• Jordan
• Josh Holmer
• Jovansonlee Cesar
• Katrina Brock
• Kieran
• Konstantinos Sideris
• Lance Carlson
• Lauri Apple
• Maciej
• Maciej Dziardziel
• Mark Catley
• Martijn de Haan
• Mathieu Rochette
• Matt Casper
• Maxime “pep” Buquet
• Michael Macias
• Michael Stock
• Mike Piccolo
• Mrmaxmeier
• Patrick Fernie
• Paul Lange
• Peter Marheine
• Pyry Kontio
• Rasmus Kaj
• Richard Dodd
• Robert Balicki
• Robert Maloney
• Ruben De Smet
• Ryan Blecher
• Sam Phippen
• Sebastian Blei
• Sergio Benitez
• Severen Redwood
• Sharad Chand
• Sid Ngeth
• Stu Black
• Sunrin SHIMURA (keen)
• Tamir Duberstein
• Taryn Hill
• Tess Griffin
• Tim Brooks
• Tobias Schottdorf
• Tom Houlé
• Tshepang Lekhonkhobe
• Will Murphy
• William Murphy
• benaryorg
• bippityboppity
• debris
• derekdreery
• jacob
• jethrogb
• kardeiz
• king6cong
• klieth
• pfernie
• theduke
• wangcong

Happy holidays!

This release contains no major code changes. There are a handful of minor bug fixes (the most notable being that SQLite no longer panics when we receive SQLITE_BUSY), but most changes are related to ensuring that our API documentation renders better.

We do not expect any further changes to the codebase of any kind (other than the version number) between this release and 1.0.0. Assuming no critical issues are found with this release candidate, the code as it exists at this point will be released as 1.0.0 on 2017-12-30.

This release contains 2 major changes from 0.99.0. The first is not news, we have removed all deprecated code from the codebase. However, this release also contains some major restructuring of the query_dsl module.

Traits related to the construction of queries, such as SelectDsl, FilterDsl, etc. Have been merged into a single QueryDsl trait. Traits related to the execution of queries, such as ExecuteDsl and LoadDsl have been merged into a single RunQueryDsl trait. The individual method traits still exist under the query_dsl::methods module, but they are no longer exported from prelude.

Though we promised there would be no significant changes other than documentation, during our process of documenting this module, it became clear that making this change would make discovering how to use Diesel's query builder dramatically easier. It also gives us a much more centralized place to document these logically grouped methods. While we do not expect this change to break many apps, it is significant enough to warrant an early release.

Most applications should not need to care about this change. Code which is just doing use diesel::prelude::* and calling these methods will continue to work with no changes (though error messages will be improved if you make a mistake).

However, if you had code that was implementing QueryFragment or Query, and expected to be able to call .execute, .load, or similar on it (such as the Pagination helper in crates.io), you will need to add impl<Conn> RunQueryDsl<Conn> for YourType.

If you have code that is calling query builder methods generically (e.g. if you have where T: FilterDsl<Something>, you will likely need to explicitly import things from query_dsl::methods

In addition to those changes, there are some minor improvements to #[derive(QueryableByName)] which we had planned on releasing as 0.99.2.

Stability

With this release, 0.99.x will only receive bug fixes and security patches. No new features will be backported to that branch. However, 0.99 can be considered our first "LTS" release. While we have not yet determined what exactly that means for Diesel, you can be assured that release line will continue to be supported for as long as there is demand.

We do not plan on having a 1.0.0.beta2, but there may be additional minor breaking changes in that release if it is needed. If there are any code changes between now and 1.0.0, even non-breaking ones, we will have a release candidate before the final release.

Looking Ahead

As with 0.99.0, we expect that the only significant change between this release and 1.0.0 will be documentation. We expect that the final release of 1.0.0 will be before the end of the year.

Our only blocker for a final 1.0 release continues to be documentation. There is a lot of work to do before the end of the year. We need help from the community to reach our goal of releasing this year. If you're interested in helping out, join the impl period working group channel.

This release is by far the largest Diesel has ever had. It serves 2 purposes. You can consider this release to be a beta for 1.0. However, 1.0 will have an important significant difference. Anything that is deprecated as of this release will not be present in the 1.0 release. This includes functions which were newly deprecated in 0.99. We know this may introduce a migration burden for some people, so we will continue to support the 0.99 line with bug fixes as long as there is demand and it is reasonable to do so.

Headline Features

This release is mainly focused on ergonomics. Our main new feature is the sql_query function. This is a new API which behaves similarly to sql, but it is entirely focused on cases where you want to write the entire query yourself. The main difference from sql is that you do not need to specify the return type of the query, and values are fetched by name rather than by index. This feature is still early, and there's a lot of features still to come (specifically evolving #[derive(QueryableByName)], but we think this feature will ease a lot of pains for cases where Diesel doesn't quite do what you need.

Additionally, you can now use tuples for inserts the same as you can for updates. If you've ever wanted to insert a row with just 1 or 2 values, and been annoyed that you needed a struct that you're only using in this one place, this feature will make you happy. We'll have new guides highlighting this feature soon.

Additionally, this release comes with a ton of quality of life features. Many of these changes are focused around making it easier to introduce line breaks naturally in your code. For example, .filter is now implemented on UpdateStatement, meaning you can write update(foo).filter(bar) instead of update(foo.filter(bar)). We've also introduced new APIs for insert and PG upsert which will have similar readability improvements.

Breaking Changes

This release includes more deprecations than any release prior. In particular, insert has been deprecated, along with our entire PG upsert API. All deprecations in this release have direct replacements, which will lead to code which formats much more nicely. It should be a mostly mechanical replacement for most apps. See the CHANGELOG file for details.

Growing the Team

With this release, we'd like to welcome several new members to the Diesel committer team. @weiznich, @notryanb, and @katrinabrock you've all done excellent work and we're very excited to officially welcome you to the team!

Additional Thanks

In addition to the Diesel core and committer teams, 10 people contributed to this release. A huge thank you to:

• Adam Perry
• Alex Kitchens
• Alexey Zabelin
• Arnar Mar Sig
• Bob
• Jordan
• Lauri Apple
• Maxime “pep” Buquet
• William Murphy
• bippityboppity

Our only remaining blockers from this release and 1.0 are documentation changes, and having this tested in the wild. Thank you to every one of our users for your support, and we look forward to Diesel 1.0 by the end of the year!

This release contains some changes to how joins work with Diesel, which we wanted to release as far in advance of 1.0 as possible. With this release, #[belongs_to] no longer generates the code required to join between two tables. The macro joinable! must be invoked instead. However, if you are using infer_schema! or diesel print-schema, these invocations will be generated based on the foreign keys in your database.

Also included in this release is the ability to rename columns. This is most useful when your columns conflict with Rust keywords. See the changelog for details.

In addition to the Diesel core team, 11 people contributed to this release. A huge thank you to:

• Alex Alvarez
• Georg Semmler
• Graham Grochowski
• JD Gonzales
• Lance Carlson
• Maciej
• Robert Balicki
• Sharad Chand
• Taryn Hill
• debris
• klieth

This is a minor bugfix release which addresses an issue with encoding of BigDecimal objects with PostgreSQL. Diesel would previously incorrectly encode certain numbers resulting in a runtime error.

This is a minor release containing a few quality of life features. We were originally planning to ship these with 1.0, but they're specifically needed by some production users.

The biggest feature here is the ability to manually specify the ON clause of a join, which is separate from the associations API. You can also use this to join to tables which otherwise have no association between them (but this will also require you to invoke enable_multi_table_joins!).

In addition to the Diesel core team, 6 people contributed to this release. A huge thank you to:

• Alex Kitchens
• Maciej Dziardziel
• Pyry Kontio
• Sunrin SHIMURA (keen)
• king6cong
• wangcong

This is a bugfix release addressing an issue with sum and avg. These were mistakenly treated as returning the same type as their argument. However, these functions return NULL when run against an empty database, which could result in errors.

This is a bugfix release addressing an issue with sum and avg. These were mistakenly treated as returning the same type as their argument. However, these functions return NULL when run against an empty database, which could result in errors.

One of the oldest issues in Diesel was that we limited the number of tables that could appear in a single query to 2. The problem was never about having more than 2 tables, but safely and correctly proving in the type system what would and could not be selected from that join.

With 0.14, that restriction has been removed. The query builder now supports joins containing an arbitrary number of tables. You may find that you need to call enable_multi_table_joins! for a few tables, but that need should go away in the future as specialization matures.

In addition to the headline feature, this release includes support for several new datatypes (including NUMERIC/DECIMAL which has been widely requested), and other small quality of life improvements. As always, you can see the CHANGELOG for the full release notes.

The Road to 1.0

A recent point of discussion among the core team has been what remaining blockers we have for releasing a version 1.0. The roadmap doesn't necessarily include everything that would make us "feature complete". It focuses on the set of changes that we think are likely to require breaking changes.

We expect that this will be the last 0.x release. You can follow the milestone here. Additionally, we all agreed that the biggest blocker to a 1.0 release is improvements to our documentation. We're going to be doing a big push in the coming months to clean things up, and are looking for help from the community. You can follow that project here, or just come join us in our gitter room to talk about how you can help.

There will be a blog post with more details about this in the coming weeks.

Contributors

In addition to the core team, 10 people contributed to this release. A huge thank you to:

• Dorian Scheidt
• FliegendeWurst
• Georg Semmler
• JD Gonzales
• Jim McGrath
• Kieran
• Ruben De Smet
• Sunrin SHIMURA (keen)
• Tshepang Lekhonkhobe
• theduke

Core Team Changes

With this release, we are also making some changes to the core team to better reflect the current active maintainers. In recognition of his fantastic work, we're pleased to welcome @Eijebong to the core team. Many early members of the team have also since moved onto other projects. To reflect that, Mike Piccolo, Matt Casper, and Sam Phippen are all being moved to the core team alumni.

This release adds support for date and time types with SQLite, allows for raw SQL to use bind parameters, and updates our dependencies (notably allowing serde 1.0).

As always, you can find the full release notes in the CHANGELOG

In addition to the core team, 11 people contributed to this release. A huge thank you to:

• Tobias Schottdorf
• Dorian Scheidt
• Danilo Bargen
• Enether
• John Gallagher
• James Kominick
• pfernie
• Blake Pettersson
• Mark Catley
• Bastien Orivel
• Sunrin SHIMURA (keen)
• kardeiz

The main feature of this release is support for PG's ON CONFLICT DO UPDATE, which brings our support for upsert on PG to nearly the entire range of possible syntax. Additionally, this release contains support for some new data types and operators, and several bug fixes.

Finally, the way that we handle joins has been going through a huge overhaul internally. For the most part this doesn't affect public API yet, but you may notice an increase in compile times, and more things "just working" the way you'd expect when working with joins. This work will hopefully lead to 3+ table joins in the next release.

As always, you can find the full release notes in the CHANGELOG

In addition to the core team, 11 people contributed to this release. A huge thank you to:

• Taryn Hill
• Eijebong
• Martijn de Haan
• Mrmaxmeier
• Daniel Durante
• Patrick Fernie
• Erich Cordoba
• Sid Ngeth
• pfernie
• John Gallagher
• theduke