Make drift generate code in multiple files.
build_runnerto change the generated code.
drift_dev package supports a range of options that control how code is generated. In most cases, the default settings should be sufficient. But if you want to try out new features faster or configure how drift-generated code looks like, you can use the available options listed below. You can also see the section on recommended options for advice on which options to use.
To use the options, create a
build.yaml file in the root of your project (e.g. next to your
# build.yaml. This file is quite powerful, see https://pub.dev/packages/build_config targets: $default: builders: drift_dev: options: store_date_time_values_as_text: true
At the moment, drift 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 drift generates another class to hold the result of generated select queries, this flag controls whether drift should override
hashCodein those classes. In recent versions, it will also override
toStringif this option is enabled.
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
.driftfile 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(deprecated): Generates a named
connect()constructor on database classes that takes a
DatabaseConnectioninstead of a
QueryExecutor. This option was deprecated in drift 2.5 because
true): Controls whether drift 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
raw_result_set_data: The generator will expose the underlying
QueryRowfor generated result set classes
true): Applies type converters to variables in compiled statements.
true): Generates a
T?for nullable columns in
copyWith. This allows to set columns back to null (by using
nullwas ignored before, making it impossible to set columns to
named_parameters: Generates named parameters for named variables in SQL queries.
named_parameters_always_required: All named parameters (generated if
true) will be required in Dart.
true): Generates a function parameter for Dart placeholders in SQL. The function has a parameter for each table that is available in the query, making it easier to get aliases right when using Dart placeholders.
store_date_time_values_as_text: Whether date-time columns should be stored as ISO 8601 string instead of a unix timestamp. For more information on these modes, see datetime options.
snake_case): Controls how the table and column names are re-cased from the Dart identifiers. The possible values are
write_to_columns_mixins: Whether the
toColumnsmethod should be written as a mixin instead of being added directly to the data class. This is useful when using existing row classes, as the mixin is generated for those as well.
fatal_warnings: When enabled (defaults to
false), warnings found by
drift_devin the build process (like syntax errors in SQL queries or unresolved references in your Dart tables) will cause the build to fail.
preamble: This option is useful when using drift as a standalone part builder or when running a modular build. In these setups, the
preambleoption defined by the source_gen package would have no effect, which is why it has been added as an option for the drift builders.
Assumed SQL environment
You can configure the SQL dialect you want to target with the
sql build option. When using sqlite, you can further configure the assumed sqlite3 version and enabled extensions for more accurate analysis.
Note that these options are used for static analysis only and don't have an impact on the actual sqlite version at runtime.
To define the sqlite version to use, set
sqlite.version to the
targets: $default: builders: drift_dev: options: sql: dialect: sqlite options: version: "3.34"
With that option, the generator will emit warnings when using features introduced in more recent sqlite versions. For instance, using more than one upsert clause is not supported in 3.34, so an error would be reported. Currently, the generator can't provide compatibility checks for versions below 3.34, which is the minimum version needed in options.
Multi-dialect code generation
Thanks to community contributions, drift has in-progress support for Postgres and MariaDB. You can change the
dialect option to
mariadb to generate code for those database management systems.
In some cases, your generated code might have to support more than one DBMS. For instance, you might want to share database code between your backend and a Flutter app. Or maybe you're writing a server that should be able to talk to both MariaDB and Postgres, depending on what the operator prefers. Drift can generate code for multiple dialects - in that case, the right SQL will be chosen at runtime when it makes a difference.
To enable this feature, remove the
dialect option in the
sql block and replace it with a list of
targets: $default: builders: drift_dev: options: sql: dialects: - sqlite - postgres options: version: "3.34"
Note: This enables extensions in the analyzer for custom queries only. For instance, when the
json1 extension is enabled, the
json functions can be used in drift 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 a
targets: $default: builders: drift_dev: options: sql: dialect: sqlite options: modules: - json1 - fts5 - math
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.
rtree: Static analysis support for the R*Tree extension. Enabling this option is safe when using a
sqlite3_flutter_libs, which compiles sqlite3 with the R*Tree extension enabled.
moor_ffi: Enables support for functions that are only available when using a
NativeDatabase. This contains
sqrtand a variety of trigonometric functions. Details on those functions are available here.
math: Assumes that sqlite3 was compiled with math functions. This module is largely incompatible with the
spellfix1: Assumes that the spellfix1 module is available. Note that this is not the case for most sqlite3 builds, including the ones shipping with
Known custom functions
modules options can be used to tell drift's analyzer that a well-known sqlite3 extension is available at runtime. In some backends (like a
NativeDatabase), it is also possible to specify entirely custom functions.
To be able to use these functions in
.drift files, you can tell drift's analyzer about them. To do so, add a
known_functions block to the options:
targets: $default: builders: drift_dev: options: sql: dialect: sqlite options: known_functions: my_function: "boolean (text, int null)"
With these options, drift will analyze queries under the assumption that a SQL function called
my_function taking a non-nullable textual value an a nullable integer will return a non-null value that drift can interpret as a boolean.
The syntax for a function type is defined as
<return type> (<argument types>). Each type consists of an arbitrary word used to determine column affinity, with drift also supporting
BOOLEAN as type hints. Then, the optional
NULL keyword can be used to indicate whether the type is nullable.
In general, we recommend using the default options. However, you can disable some default drift 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.
Configure your build to allow drift dataclasses to be seen by other builders.