moor_generator package has some options that control how the
code is generated. Note that, in most cases, the default settings
should be sufficient. See the section on recommended settings below.
To use the options, create a
build.yaml file in the root of your project (e.g. next
# build.yaml. This file is quite powerful, see https://pub.dev/packages/build_config targets: $default: builders: moor_generator: options: compact_query_methods: true
At the moment, moor supports these options:
write_from_json_string_constructor: boolean. Adds a
.fromJsonStringfactory constructor to generated data classes. By default, we only write a
.fromJsonconstructor that takes a
override_hash_and_equals_in_result_sets: boolean. When moor generates another class to hold the result of generated select queries, this flag controls whether moor should override
hashCodein those classes.
true): For queries declared on a
@UseDaoannotation, moor used to generate three methods: A base method returning a
Selectableand then two helper methods returning a
Future. As the
Selectableclass contains its own methods to convert it to a
Future, the two later methods only exist for backwards compatibility. When this flag is enabled, moor won’t write them at all. This flag is enabled by default in moor 3.0, but it can still be disabled.
skip_verification_code: Generated tables contain a significant chunk of code to verify integrity of inserted data and report detailed errors when the integrity is violated. If you’re only using inserts with SQL, or don’t need this functionality, enabling this flag can help to reduce the amount generated code.
use_data_class_name_for_companions: By default, the name for companion classes is based on the table name (e.g. a
@DataClassName('Users') class UsersTable extends Tablewould generate a
UsersTableCompanion). With this option, the name is based on the data class (so
UsersCompanionin this case).
true): When serializing columns declared inside a
.moorfile from and to json, use their sql name instead of the generated Dart getter name (so a column named
user_namewould also use
user_nameas a json key instead of
userName). You can always override the json key by using a
JSON KEYcolumn constraint (e.g.
user_name VARCHAR NOT NULL JSON KEY userName)
generate_connect_constructor: Generate necessary code to support the isolate runtime. This is a build option because isolates are still experimental. This will be the default option eventually.
sqlite_modules: This list can be used to enable sqlite extensions, like those for json or full-text search. Modules have to be enabled explicitly because they’re not supported on all platforms. See the following section for details.
eagerly_load_dart_ast: Moor’s builder will load the resolved AST whenever it encounters a Dart file, instead of lazily when it reads a table. This is used to investigate rare builder crashes.
legacy_type_inference: Use the old type inference from moor 1 and 2. Note that
use_experimental_inferenceis now the default and no longer exists. If you’re using this flag, please open an issue and explain how the new inference isn’t working for you, thanks!
true): Controls whether moor will write the
toCompanionmethod in generated data classes.
false): The fields generated in generated data, companion and result set classes are final by default. You can make them mutable by setting
Note: This enables extensions in the analyzer for custom queries only. For instance, when the
json1 extension is
json functions can be used in moor files. This doesn’t necessarily
mean that those functions are supported at runtime! Both extensions are available on iOS 11 or later. On Android, they’re
only available when using
moor_ffi. See our docs for more details on them.
targets: $default: builders: moor_generator: options: sqlite_modules: - json1 - fts5 - moor_ffi
We currently support the following extensions:
- json1: Support static analysis for
json_functions in moor files
- fts5: Support
CREATE VIRTUAL TABLEstatements for
fts5tables and the
MATCHoperator. Functions like
bm25are available as well.
moor_ffi: Enables support for functions that are only available when using
moor_ffi. This contains
sqrtand a variety of trigonometric functions. Details on those functions are available here.
In general, we recommend using the default options.
You can disable some default moor features and reduce the amount of generated code with the following options:
skip_verification_code: true: You can remove a significant portion of generated code with this option. The downside is that error messages when inserting invalid data will be less specific.
data_class_to_companions: false: Don’t generate the
toCompanionmethod on data classes. If you don’t need that method, you can disable this option.
Using moor classes in other builders
Starting with moor 2.4, it’s possible to use classes generated by moor in other builders.
Due to technicalities related to Dart’s build system and
source_gen, this approach requires a custom configuration
and minor code changes. Put this content in a file called
build.yaml next to your
targets: $default: builders: # disable the default generator and enable the one emitting a .moor.dart file moor_generator: enabled: false moor_generator|moor_generator_not_shared: enabled: true # If needed, you can configure the builder like this: # options: # skip_verification_code: true # use_experimental_inference: true # Run built_value_generator when moor is done, which is not in this target. built_value_generator|built_value: enabled: false # all other builders that need to work on moor classes should be disabled here # as well run_built_value: dependencies: ['your_package_name'] builders: # Disable moor builders. By default, those would run on each target moor_generator: enabled: false moor_generator|preparing_builder: enabled: false # we don't need to disable moor_generator_not_shared, because it's disabled by default
In all files that use generated moor code, you’ll have to replace
part 'filename.g.dart' with
If you use moor and another builder in the same file, you’ll need both
.moor.dart as part-files.
A full example is available as part of the moor repo.
If you run into any problems with this approach, feel free to open an issue on moor. At the moment, a known issue is that
other builders can emit a warning about missing
part statements in the
.moor.dart file generated by moor. This shouldn’t
affect the generated code and has been reported here.
The technicalities, explained
Almost all code generation packages use a so called “shared part file” approach provided by
It’s a common protocol that allows unrelated builders to write into the same
For this to work, each builder first writes a
.part file with its name. For instance, if you used
built_value in the same project, those part files could be called
Later, the common
source_gen package would merge the part files into a single
This works great for most use cases, but a downside is that each builder can’t see the final
file, or use any classes or methods defined in it. To fix that, moor offers an optional builder -
moor_generator|moor_generator_not_shared - that will generate a separate part file only containing
code generated by moor. So most of the work resolves around disabling the default generator of moor
and use the non-shared generator instead.
Finally, we need to the build system to run moor first, and all the other builders otherwise. This is why we split the builders up into multiple targets. The first target will only run moor, the second target has a dependency on the first one and will run all the other builders.