Module datafusion::logical_plan

This module provides a logical query plan enum that can describe queries. Logical query plans can be created from a SQL statement or built programmatically via the Table API.

Logical query plans can then be optimized and executed directly, or translated into physical query plans and executed.

Structs

DFField	DFField wraps an Arrow field and adds an optional qualifier
DFSchema	DFSchema wraps an Arrow schema and adds relation names
LogicalPlanBuilder	Builder for logical plans
StringifiedPlan	Represents some sort of execution plan, in String form

Enums

Expr	Expr is a logical expression. A logical expression is something like 1 + 1, or CAST(c1 AS int). Logical expressions know how to compute its arrow::datatypes::DataType and nullability. Expr is a central struct of DataFusion's query API.
JoinType	Join type
LogicalPlan	A LogicalPlan represents the different types of relational operators (such as Projection, Filter, etc) and can be created by the SQL query planner and the DataFrame API.
Operator	Operators applied to expressions
Partitioning	Logical partitioning schemes supported by the repartition operator.
PlanType	Represents which type of plan

Traits

FunctionRegistry	A registry knows how to build logical expressions out of user-defined function' names
Literal	Whether it can be represented as a literal expression
PlanVisitor	Trait that implements the Visitor pattern for a depth first walk of LogicalPlan nodes. pre_visit is called before any children are visited, and then post_visit is called after all children have been visited. To use, define a struct that implements this trait and then invoke "LogicalPlan::accept".
ToDFSchema	Convenience trait to convert Schema like things to DFSchema and DFSchemaRef with fewer keystrokes
UserDefinedLogicalNode	This defines the interface for LogicalPlan nodes that can be used to extend DataFusion with custom relational operators.

Functions

abs
acos
and	return a new expression with a logical AND
array	returns an array of fixed size with each argument on it.
asin
atan
avg	Create an expression to represent the avg() aggregate function
binary_expr	return a new expression l r
case	Create a CASE WHEN statement with literal WHEN expressions for comparison to the base expression.
ceil
col	Create a column expression based on a column name
concat	returns the concatenation of string expressions
cos
count	Create an expression to represent the count() aggregate function
count_distinct	Create an expression to represent the count(distinct) aggregate function
create_udaf	Creates a new UDAF with a specific signature, state type and return type. The signature and state type must match the Acumulator's implementation.
create_udf	Creates a new UDF with a specific signature and specific return type. This is a helper function to create a new UDF. The function create_udf returns a subset of all possible ScalarFunction:
display_schema	Print the schema in a compact representation to buf
exp
exprlist_to_fields	Create field meta-data from an expression, for use in a result set schema
floor
in_list	Create an in_list expression
length	returns the length of a string in bytes
lit	Create a literal expression
ln
log2
log10
lower
ltrim
max	Create an expression to represent the max() aggregate function
md5
min	Create an expression to represent the min() aggregate function
or	return a new expression with a logical OR
round
rtrim
sha224
sha256
sha384
sha512
signum
sin
sqrt
sum	Create an expression to represent the sum() aggregate function
tan
trim
trunc
upper
when	Create a CASE WHEN statement with boolean WHEN expressions and no base expression.

Type Definitions

DFSchemaRef

A reference-counted reference to a DFSchema.