ColumnWithDefaultExprUtils¶

IDENTITY column is not supported

IDENTITY_MIN_WRITER_VERSION¶

ColumnWithDefaultExprUtils uses 6 as the minimum version of a writer for writing to IDENTITY columns.

IDENTITY_MIN_WRITER_VERSION is used when:

• ColumnWithDefaultExprUtils is used to satisfyProtocol
• Protocol utility is used to determine the required minimum protocol

columnHasDefaultExpr¶

columnHasDefaultExpr(
  protocol: Protocol,
  col: StructField): Boolean

columnHasDefaultExpr is an alias of GeneratedColumn.isGeneratedColumn.

columnHasDefaultExpr is used when:

• DeltaAnalysis logical resolution rule is requested to resolveQueryColumnsByName

hasIdentityColumn¶

hasIdentityColumn(
  schema: StructType): Boolean

hasIdentityColumn returns true if the given StructType (Spark SQL) contains an IDENTITY column.

hasIdentityColumn is used when:

• Protocol utility is used for the required minimum protocol

isIdentityColumn¶

isIdentityColumn(
  field: StructField): Boolean

isIdentityColumn is used to find out whether a StructField is an identity column or not.

isIdentityColumn uses the Metadata (of the given StructField) to check the existence of the following metadata keys:

• delta.identity.start
• delta.identity.step
• delta.identity.allowExplicitInsert

isIdentityColumn is used when:

• ColumnWithDefaultExprUtils is used to addDefaultExprsOrReturnConstraints, columnHasDefaultExpr, hasIdentityColumn and removeDefaultExpressions
• IdentityColumn is requested to blockExplicitIdentityColumnInsert, getIdentityColumns, syncIdentity, updateSchema, updateToValidHighWaterMark
• DeltaCatalog is requested to alterTable and createDeltaTable
• MergeIntoCommandBase is requested to checkIdentityColumnHighWaterMarks
• WriteIntoDelta is requested to writeAndReturnCommitData

Remove Default Expressions from Table Schema¶

removeDefaultExpressions(
  schema: StructType,
  keepGeneratedColumns: Boolean = false,
  keepIdentityColumns: Boolean = false): StructType

removeDefaultExpressions...FIXME

removeDefaultExpressions is used when:

• DeltaTableUtils is requested to removeInternalWriterMetadata
• OptimisticTransactionImpl is requested to updateMetadataInternal

tableHasDefaultExpr¶

tableHasDefaultExpr(
  protocol: Protocol,
  metadata: Metadata): Boolean

tableHasDefaultExpr enforcesGeneratedColumns.

tableHasDefaultExpr is used when:

• TransactionalWrite is requested to normalizeData