Module schema 

Structs

ColumnExistsRule

Rule that checks if a column exists in the schema

ColumnNullableRule

Rule that checks if a column is nullable

ColumnTypeRule

Rule that checks if a column has a specific data type

Functions

dfq_column_exists

Creates a rule that checks if a column exists in the schema

dfq_column_not_nullable

Creates a rule that checks if a column is not nullable

dfq_column_nullable

Creates a rule that checks if a column is nullable

dfq_column_type

Creates a rule that checks if a column has a specific data type