Crate drizzle_core 

SQL building blocks shared by every Drizzle dialect.

Most users depend on the drizzle crate, which re-exports this one as drizzle::core. This crate holds the parts that do not depend on a database:

• SQL and ToSQL: SQL fragments with bound parameters.
• expr: typed expressions and functions (eq, count, coalesce, …).
• row and scope: compile-time row-type inference and query checks.
• traits: the table, column, and schema traits the macros implement.
• dialect: dialect markers and dialect-only feature gates.
• error::DrizzleError: the error type every driver returns.

Examples

Building a fragment by hand. Value stands in for a driver’s value type (SQLiteValue, PostgresValue, …):

use drizzle_core::{SQL, Token};

let query: SQL<'_, Value> = SQL::raw("SELECT * FROM")
    .append(SQL::ident("users"))
    .push(Token::WHERE)
    .append(SQL::ident("id"))
    .push(Token::EQ)
    .append(SQL::param(Value(42)));

assert_eq!(query.sql(), r#"SELECT * FROM "users" WHERE "id" = ?"#);
assert_eq!(query.params().count(), 1);

Compile-time checks

Queries are checked when they are built and run, not when they reach the database. The compiler rejects a query that:

• reads a table it never added with .from(...) or a join (scope, MarkerScopeValidFor);
• decodes a column from the nullable side of an outer join as T instead of Option<T> (MarkerColumnCountValid);
• selects a non-aggregate column that is not in GROUP BY (MarkerAggValidFor);
• calls a clause out of order, such as .r#where(...) after .limit(...) (ClauseAllowed);
• uses a function the dialect lacks (DialectSupports).

no_std Support

This crate supports no_std environments with an allocator:

# With std (default)
drizzle-core = "0.2"

# no_std with allocator
drizzle-core = { version = "0.2", default-features = false, features = ["alloc"] }

Re-exports

pub use bind::BindValue;

pub use bind::NullableBindValue;

pub use bind::ValueTypeForDialect;

pub use builder::BuilderInit;

pub use builder::ClauseAllowed;

pub use builder::ExecutableState;

pub use builder::InsertColumnsSet;

pub use builder::clause;

pub use derived::Derived;

pub use derived::DerivedField;

pub use dialect::DialectSupports;

pub use dialect::DialectTypes;

pub use dialect::MySQLDialect;

pub use dialect::PostgresDialect;

pub use dialect::SQLiteDialect;

pub use dialect::feature;

pub use join::Join;

pub use join::JoinType;

pub use pagination::PaginationArg;

pub use param::OwnedParam;

pub use param::Param;

pub use param::ParamBind;

pub use param::ParamSet;

pub use relation::JoinExplicit;

pub use relation::JoinForward;

pub use relation::JoinKey;

pub use relation::JoinReverse;

pub use relation::Joinable;

pub use relation::Relation;

pub use relation::SchemaHasTable;

pub use row::DecodeSelectedRef;

pub use row::ExprValueType;

pub use row::FromDrizzleRow;

pub use row::GroupByIdentity;

pub use row::HasSelectModel;

pub use row::IntoGroupBy;

pub use row::IntoSelectTarget;

pub use row::JoinedStarRow;

pub use row::MarkerAggValidFor;

pub use row::MarkerColumnCountValid;

pub use row::MarkerScopeValidFor;

pub use row::NullProbeRow;

pub use row::PkGroup;

pub use row::ResolveRow;

pub use row::RowColumnList;

pub use row::SQLTypeToRust;

pub use row::SelectAs;

pub use row::SelectAsFrom;

pub use row::SelectCols;

pub use row::SelectExpr;

pub use row::SelectStar;

pub use row::SelectTableFields;

pub use row::TableFields;

pub use row::WrapNullable;

pub use schema::OrderBy;

pub use schema::OrderTerm;

pub use schema::Ordered;

pub use schema::asc;

pub use schema::desc;

pub use scope::AliasKey;

pub use scope::FromMarker;

pub use scope::FullJoin;

pub use scope::HasScope;

pub use scope::InnerJoin;

pub use scope::JoinStep;

pub use scope::Lateral;

pub use scope::LeftJoin;

pub use scope::OuterJoined;

pub use scope::RightJoin;

pub use scope::ScopeContains;

pub use scope::ScopeEntry;

pub use scope::Scoped;

pub use scope::SelectSources;

pub use scope::SetOperand;

pub use scope::Src;

pub use sql::ColumnDialect;

pub use sql::ColumnFlags;

pub use sql::ColumnRef;

pub use sql::ColumnSqlRef;

pub use sql::ConstraintRef;

pub use sql::EnumVariantRef;

pub use sql::ForeignKeyRef;

pub use sql::OwnedSQL;

pub use sql::OwnedSQLChunk;

pub use sql::PrimaryKeyRef;

pub use sql::SQL;

pub use sql::SQLChunk;

pub use sql::SQLEnumVariants;

pub use sql::TableDialect;

pub use sql::TableRef;

pub use sql::TableSqlRef;

pub use sql::Token;

pub use placeholder::*;

pub use traits::*;

Modules

bind

builder

conv

Value-conversion helpers shared by the dialect crates’ value decoding.

cte

Driver-neutral common table expression types.

derived

Typed derived-table projections.

dialect

Dialect markers, per-dialect type mappings, and dialect-only features.

error

The error type shared by every Drizzle crate and driver.

expr

Type-safe SQL expressions: comparisons, logic, aggregates and functions.

helpers

Free functions that render single SQL clauses (SELECT ..., WHERE ..., LIMIT ..., UNION, …).

join

JOIN keywords and the macros dialect crates use to build join helpers.

pagination

param

placeholder

prepared

relation

Traits that describe foreign-key relations between tables, generated by the table and schema macros.

row

Row type inference and row decoding for SELECT queries.

schema

Schema metadata for database enums, and ORDER BY terms.

scope

Compile-time checks that a query only reads tables it has joined.

sql

tracing

Macros that emit tracing events for queries and transactions.

traits

Traits for schema items (tables, columns, indexes, views, …) and SQL rendering.

types

Re-exports SQL type markers and type-level compatibility traits.

Macros

drizzle_trace_query

Emits a debug-level drizzle.query event with the SQL text and parameter count.

drizzle_trace_tx

Emits an info-level drizzle.transaction event for a transaction step (begin, commit, rollback).

impl_join_arg_trait

Generates a dialect’s JoinArg trait: what .join(...) and its variants accept.

impl_join_helpers

Generates free functions that render join clauses (join, left_join, natural_full_outer_join, …) for one dialect.

impl_try_from_int

Implements TryFrom<int> for several integer types by converting to i64 and calling the type’s TryFrom<i64>.

tag

Defines a Tag type in one line.

Enums

Dialect

The SQL dialect a value type or schema targets, known at runtime. A supported SQL database: SQLite, PostgreSQL or MySQL.