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AliasAwareOutputExpression Unary Physical Operators

AliasAwareOutputExpression is an extension of the UnaryExecNode abstraction for unary physical operators with the output named expressions.

Contract

Output Named Expressions

outputExpressions: Seq[NamedExpression]

Output NamedExpressions

Used when:

  • AliasAwareOutputExpression is requested for the aliasMap

Implementations

aliasMap

aliasMap: AttributeMap[Attribute]

aliasMap is a collection of AttributeReference expressions (of the Alias expressions with the AttributeReference expressions in the output named expressions) and the Aliases converted to Attributes.

Lazy Value

aliasMap is a Scala lazy value to guarantee that the code to initialize it is executed once only (when accessed for the first time) and the computed value never changes afterwards.

Learn more in the Scala Language Specification.

aliasMap is used when:

hasAlias

hasAlias: Boolean

hasAlias is true when the aliasMap is not empty.

hasAlias is used when:

normalizeExpression

normalizeExpression(
  exp: Expression): Expression

normalizeExpression...FIXME

normalizeExpression is used when:

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