Trait SqlDialect

pub trait SqlDialect: TrustedBackend {
    type ReturningClause;
    type OnConflictClause;
    type InsertWithDefaultKeyword;
    type BatchInsertSupport;
    type ConcatClause;
    type DefaultValueClauseForInsert;
    type EmptyFromClauseSyntax;
    type ExistsSyntax;
    type ArrayComparison;
    type SelectStatementSyntax;
    type AliasSyntax;
}

This trait provides various options to configure the generated SQL for a specific backend.

Accessing anything from this trait is considered to be part of the public API. Implementing this trait is not considered to be part of diesel’s public API, as future versions of diesel may add additional associated constants here.

Each associated type is used to configure the behaviour of one or more QueryFragment implementations by providing a custom QueryFragment<YourBackend, YourSpecialSyntaxType> implementation to specialize on generic QueryFragment<DB, DB::AssociatedType> implementations.

Required Associated Types

type ReturningClause

Configures how this backend supports RETURNING clauses

This allows backends to opt in RETURNING clause support and to provide a custom QueryFragment implementation for ReturningClause

type OnConflictClause

Configures how this backend supports ON CONFLICT clauses

This allows backends to opt in ON CONFLICT clause support

type InsertWithDefaultKeyword

Configures how this backend handles the bare DEFAULT keyword for inserting the default value in a INSERT INTO VALUES clause

This allows backends to opt in support for DEFAULT value expressions for insert statements

type BatchInsertSupport

Configures how this backend handles Batch insert statements

This allows backends to provide a custom QueryFragment implementation for BatchInsert

type ConcatClause

Configures how this backend handles the Concat clauses in select statements.

This allows backends to provide a custom QueryFragment implementation for Concat

type DefaultValueClauseForInsert

Configures how this backend handles the DEFAULT VALUES clause for insert statements.

This allows backends to provide a custom QueryFragment implementation for DefaultValues

type EmptyFromClauseSyntax

Configures how this backend handles empty FROM clauses for select statements.

This allows backends to provide a custom QueryFragment implementation for NoFromClause

type ExistsSyntax

Configures how this backend handles EXISTS() expressions.

This allows backends to provide a custom QueryFragment implementation for Exists

type ArrayComparison

Configures how this backend handles IN() and NOT IN() expressions.

This allows backends to provide custom QueryFragment implementations for In, NotIn and Many

type SelectStatementSyntax

Configures how this backend structures SELECT queries

This allows backends to provide custom QueryFragment implementations for SelectStatement and BoxedSelectStatement SelectStatement and BoxedSelectStatement

type AliasSyntax

Configures how this backend structures SELECT queries

This allows backends to provide custom QueryFragment implementations for Alias<T>

Implementors

impl SqlDialect for Mysql

Available on crate feature mysql_backend only.

type ReturningClause = DoesNotSupportReturningClause

type OnConflictClause = MysqlOnConflictClause

type InsertWithDefaultKeyword = IsoSqlDefaultKeyword

type BatchInsertSupport = PostgresLikeBatchInsertSupport

type DefaultValueClauseForInsert = MysqlStyleDefaultValueClause

type EmptyFromClauseSyntax = AnsiSqlFromClauseSyntax

type SelectStatementSyntax = AnsiSqlSelectStatement

type ExistsSyntax = AnsiSqlExistsSyntax

type ArrayComparison = AnsiSqlArrayComparison

type ConcatClause = MysqlConcatClause

type AliasSyntax = AsAliasSyntax

impl SqlDialect for Pg

Available on crate feature postgres_backend only.

type ReturningClause = PgLikeReturningClause

type OnConflictClause = PgOnConflictClause

type InsertWithDefaultKeyword = IsoSqlDefaultKeyword

type BatchInsertSupport = PostgresLikeBatchInsertSupport

type ConcatClause = ConcatWithPipesClause

type DefaultValueClauseForInsert = AnsiDefaultValueClause

type EmptyFromClauseSyntax = AnsiSqlFromClauseSyntax

type SelectStatementSyntax = AnsiSqlSelectStatement

type ExistsSyntax = AnsiSqlExistsSyntax

type ArrayComparison = PgStyleArrayComparison

type AliasSyntax = AsAliasSyntax

impl SqlDialect for Sqlite

Available on crate feature sqlite only.

type ReturningClause = DoesNotSupportReturningClause

type OnConflictClause = SqliteOnConflictClause

type InsertWithDefaultKeyword = DoesNotSupportDefaultKeyword

type BatchInsertSupport = SqliteBatchInsert

type ConcatClause = ConcatWithPipesClause

type DefaultValueClauseForInsert = AnsiDefaultValueClause

type EmptyFromClauseSyntax = AnsiSqlFromClauseSyntax

type SelectStatementSyntax = AnsiSqlSelectStatement

type ExistsSyntax = AnsiSqlExistsSyntax

type ArrayComparison = AnsiSqlArrayComparison

type AliasSyntax = AsAliasSyntax