Crate butane

Modules

• custom
  For supporting additional types with the Pg backend (or other future backends).
• db
• migrations
  For working with migrations. If using the butane CLI tool, it is not necessary to use these types directly.
• prelude
  Prelude module to improve ergonomics.
• query
  Types to support database queries. Most users will use the query!, filter!, and find! macros instead of using this module directly.

Macros

• colname
  Type-safe way to refer to a column name. Use as colname!(MODEL_TYPE, FIELD_NAME). E.g. For a model type Foo with a field bar, colname!(Foo, bar) would return “bar”, but colname!(Foo, bat)would be a compiler error (assumingFoo` does not have such a field.
• filter
  Macro to construct a BoolExpr (for use with a Query) from an expression with Rust syntax.
• find
  Finds a specific database object.
• query
  Constructs a filtered database query.

Structs

• ForeignKey
  Used to implement a relationship between models.
• Many
  Used to implement a many-to-many relationship between models.
• ObjectState
  Used internally by butane to track state about the object.

Enums

• Error
  Butane errors.
• SqlType
  Enumeration of the types a database value may take.
• SqlVal
  A database value.
• SqlValRef

Traits

• AsPrimaryKey
  Trait for referencing the primary key for a given model. Used to implement ForeignKey equality tests.
• DataObject
  An object in the database.
• DataResult
  A type which may be the result of a database query.
• FieldType
  Type suitable for being a database column.
• FromSql
  Used to convert a SqlVal or SqlValRef into another type.
• ToSql
  Used to convert another type to a SqlVal or SqlValRef.

Type Definitions

• Result

Attribute Macros

• butane_type
  Attribute macro which marks a type as being available to butane for use in models.
• dataresult
  Attribute macro which generates an implementation of DataResult. Continuing with our blog post example from model, we could create a DataResult with only some of the fields from Post (to avoid fetching all of them in a query).
• model
  Attribute macro which marks a struct as being a data model and generates an implementation of DataObject. This macro will also write information to disk at compile time necessary to generate migrations

Derive Macros

• FieldType