Internal implementation of the user-facing Catalog.
A helper class that enables substitution using syntax like
${var}, ${system:var} and ${env:var}.
A helper class that enables substitution using syntax like
${var}, ${system:var} and ${env:var}.
Variable substitution is controlled by SQLConf.variableSubstituteEnabled.
All classes in this package are considered an internal API to Spark and are subject to change between minor releases.