Crate diesel [] [src]

Diesel is an ORM and query builder designed to reduce the boilerplate for database interactions. A getting started guide can be found on our website.

Reexports

pub use self::insertable as persistable;
pub use prelude::*;
pub use sqlite::query_builder::functions::*;
pub use result::Error::NotFound;

Modules

associations

Traits related to relationships between multiple tables.

backend
connection
data_types

Structs to represent the primitive equivalent of SQL types where there is no existing Rust primitive, or where using it would be confusing (such as date and time types). This module will re-export all backend specific data structures when compiled against that backend.

expression

AST types representing various typed SQL expressions. Almost all types implement either Expression or AsExpression.

expression_methods

Adds various methods to construct new expressions. These traits are exported by default, and implemented automatically.

helper_types

Provide helper types for concisely writing the return type of functions. As with iterators, it is unfortunately difficult to return a partially constructed query without exposing the exact implementation of the function. Without higher kinded types, these various DSLs can't be combined into a single trait for boxing purposes.

migrations

Provides functions for maintaining database schema.

mysql
pg
prelude

Re-exports important traits and types. Meant to be glob imported when using Diesel.

query_builder

Contains traits responsible for the actual construction of SQL statements

query_source

Types in this module are mostly internal and automatically generated. You shouldn't need to interact with these types during normal usage, other than the methods on Table

result
row
sqlite
types

Types which represent a native SQL data type, and the conversions between them and Rust primitives. The structs in this module are only used as markers to represent a SQL type, and shouldn't be used in your structs. See the documentation for each type to see the Rust types that can be used with a corresponding SQL type. Additional types can be added by other crates.

Macros

BelongsTo

Defines a one-to-one association for the child table. This macro should be called with the name of the parent struct, followed by any options, followed by the entire struct body. The struct must be annotated with #[table_name(name_of_table)]. Both the parent and child structs must implement Identifiable.

HasMany

Defines a one-to-many association for the parent table. This macro is only required if you need to join between the two tables. This macro should be called with the name of the child table, followed by any options, followed by the entire struct body. The struct must be annotated with #[table_name(name_of_table)]. Both the parent and child structs must implement Identifiable.

debug_sql

Takes a query QueryFragment expression as an argument and returns a string of SQL with placeholders for the dynamic values.

embed_migrations

This macro will read your migrations at compile time, and embed a module you can use to execute them at runtime without the migration files being present on the file system. This is useful if you would like to use Diesel's migration infrastructure, but want to ship a single executable file (such as for embedded applications). It can also be used to apply migrations to an in memory database (Diesel does this for its own test suite).

impl_AsChangeset

Implements the AsChangeset trait for a given struct. This macro should be called with the name of the table you wish to use the struct with, followed by the entire struct body. This macro mirrors #[as_changeset] from diesel_codegen

impl_Identifiable

Implements the Identifiable trait for a reference to a given struct. This macro should be called by copy/pasting the definition of the struct into it.

impl_Insertable

Implements the Insertable trait for a given struct. This macro should be called with the name of the table you wish to use the struct with, followed by the entire struct body.

impl_query_id
infer_schema

Queries the database for the names of all tables, and calls infer_table_from_schema! for each one. A schema name can optionally be passed to load from schemas other than the default. If a schema name is given, the inferred tables will be wrapped in a module with the same name.

infer_table_from_schema

Establishes a database connection at compile time, loads the schema information about a table's columns, and invokes table! for you automatically. For tables in a schema other than the default, the table name should be given as "schema_name.table_name".

infix_predicate

Useful for libraries adding support for new SQL types. Apps should never need to call this

no_arg_sql_function

Declare a 0 argument SQL function for use in your code. This will generate a unit struct, which is an expression representing calling this function. See now for example output. now was generated using:

numeric_expr

Indicates that an expression allows all numeric operators. If you create new SQL functions that return a numeric type, you should invoke this macro that type. Unfortunately, Rust disallows us from automatically implementing Add for types which implement Expression, under its orphan rules.

operator_allowed

Implements the Rust operator for a given type. If you create a new SQL function, which returns a type that you'd like to use an operator on, you should invoke this macro. Unfortunately, Rust disallows us from automatically implementing Add and other traits from std::ops, under its orphan rules.

postfix_expression
postfix_predicate

Useful for libraries adding support for new SQL types. Apps should never need to call this.

print_sql

Takes takes a query QueryFragment expression as an argument and prints out the SQL with placeholders for the dynamic values.

sql_function

Declare a sql function for use in your code. Useful if you have your own SQL functions that you'd like to use. You can optionally provide a doc string as well. $struct_name should just be any unique name. You will not need to reference it in your code, but it is required due to the fact that concat_idents! is useless.

table

Specifies that a table exists, and what columns it has. This will create a new public module, with the same name, as the name of the table. In this module, you'll find a unit struct named table, and a unit struct with the names of each of the columns. In the definition, you can also specify an additional set of columns which exist, but should not be selected by default (for example, for things like full text search)

Functions

delete

Creates a delete statement. Will delete the records in the given set. Because this function has a very generic name, it is not exported by default.

insert

Creates an insert statement. Will add the given data to a table. This function is not exported by default. As with other commands, the resulting query can return the inserted rows if you choose.

select

Creates a bare select statement, with no from clause. Primarily used for testing diesel itself, but likely useful for third party crates as well. The given expressions must be selectable from anywhere.

update

Creates an update statement. Helpers for updating a single row can be generated by deriving AsChangeset