Constraints Utility¶

Extracting All Constraints¶

getAll(
  metadata: Metadata,
  spark: SparkSession): Seq[Constraint]

getAll extracts CHECK constraints (from the given table metadata).

getAll extracts invariants (from the schema of the given table metadata).

In the end, getAll returns the CHECK constraints and invariants.

getAll is used when:

• TransactionalWrite is requested to write data out

Extracting Check Constraints from Table Metadata¶

getCheckConstraints(
  metadata: Metadata,
  spark: SparkSession): Seq[Constraint]

getCheckConstraints extracts Check constraints from the delta.constraints.-keyed entries in the configuration of the given Metadata:

• The name is the key without the delta.constraints. prefix
• The expression is the value parsed

getCheckConstraints is used when:

• Constraints utility is used to extract all constraints
• Protocol utility is used to determine the required minimum protocol