Module expr

Expressions in RisingWave.

All expressions are implemented under the Expression trait.

Construction

Expressions can be constructed by build_func() function, which returns a BoxedExpression.

They can also be transformed from the prost ExprNode using the build_from_prost() function.

Evaluation

Expressions can be evaluated using the eval function.

Re-exports

pub use super::ExprError;

pub use super::Result;

Modules

and_or 🔒

For expression that only accept two nullable arguments as input.

build 🔒

expr_input_ref 🔒

expr_literal 🔒

expr_some_all 🔒

expr_udf 🔒

test_utils

Helper functions to construct prost [ExprNode] for test.

value 🔒

wrapper 🔒

Structs

Context

An optional context that can be used in a function.

InputRefExpression

A reference to a column in input relation.

LiteralExpression

A literal expression.

LogReport

Log the error to report an error during evaluation.

NonStrictExpression

An type-safe wrapper that indicates the inner expression can be evaluated in a non-strict manner, i.e., developers can directly call eval_infallible and eval_row_infallible without checking the result.

Enums

ValueImpl

The type-erased return value of an expression.

ValueRef

The generic reference type of ValueImpl. Used as the arguments of expressions.

Traits

EvalErrorReport

Report an error during evaluation.

Expression

Interface of an expression.

ExpressionBoxExt

Extension trait for boxing expressions.

Functions

build_batch_expr_from_prost

Build a strict or non-strict expression according to expr context.

build_from_pretty

Build an expression from a string.

build_from_prost

Build an expression from protobuf.

build_func

Build an expression in FuncCall variant.

build_func_non_strict

Build an expression in FuncCall variant in non-strict mode.

build_non_strict_from_prost

Build an expression from protobuf in non-strict mode.

Type Aliases

BoxedExpression

An owned dynamically typed Expression.