Metadata and data messages

This topic describes the structure and content of the Metadata and Data messages produced by the Replicate Microsoft Azure Event Hubs endpoint.

Metadata message
Field	Type	Description
schemaId	String	The unique identifier of the Avro schema.
lineage	Structure	Information about the origin of the data (Replicate server, task, table, and so on)
server	String	The name of the Replicate server.
task	String	The name of the task.
schema	String	The name of the database schema.
table	String	The name of the table.
tableVersion	Integer	Replicate maintains a version number of the structure of source table. Upon DDL change on the source, the version is increased and a new metadata message is produced.
timestamp	String	The date and time of the metadata message.
tableStructure	Structure	Describes the structure of the table.
tableColumns	Structure	Contains the list of columns and their properties.
{columns}	Structure	For each column, a record with the below properties.
ordinal	Integer	The position of the column in the record.
type	String	The column data type.
length	Integer	The maximum size of the data (in bytes) permitted for the column.
precision	Integer	For NUMERIC data type, the maximum number of digits required to represent the value.
scale	Integer	For NUMERIC data type, the maximum number of digits to the right of the decimal point permitted for a number.
primaryKeyPosition	Integer	The position of the column in the table’s Primary Key. or Unique Index. The value is zero if the column is not part of the table’s Primary Key.
dataSchema	String	The Avro schema for deserializing the Data messages.

Data message
Field	Type	Description
headers	Structure	Information about the current record.
operation	Enum	The operation type. Full Load (Replicate transfers the existing records from source table) REFRESH – insert of a record during Full Load stage. CDC (Replicate transfers the changes from source table) INSERT – insertion of new record UPDATE – update of existing record DELETE – deletion of a record
changeSequence	String	A monotonically increasing change sequencer that is common to all change tables of a task. Use this field to order the records in chronological order. Applicable to CDC operations.
timestamp	String	The original change UTC timestamp. Applicable to CDC operations.
streamPosition	String	The source CDC stream position. Applicable to CDC operations.
transactionId	String	The ID of the transaction that the change record belongs to. Use this field to gather all changes of a specific transaction. Applicable to CDC operations.
changeMask	String	Indicates which data columns were changed in the source table. The change mask is a string of hexadecimal digits, representing a bitmask of data columns in little-endian order. The bit position in the change mask is based on the ordinal of the column in the metadata message of that table. This means that if there are 10 data columns, they occupy bits 0 to 9 in the bitmask. If UPDATE mask is 0B hexadecimal, which is 1011 binary – it means that the columns at ordinals 1, 2 and 4 were changed. The following describes the bit semantics: For INSERT records, all the inserted columns have the associated bits set. For DELETE records, only primary-key (or unique index) columns have the associated bits set. This allows an applier to construct a DELETE statement without having to find the primary key fields from another source. For UPDATE records, each column with a changed value will have the associated bit set. Information note LOB columns are not included in the changeMask bit.
columnMask	String	Indicates which data columns are present in the message. Usually, this will include all of the table columns. Information note When replicating from an Oracle source without full supplemental logging, some columns might not be present in the data, since they could not be replicated. The column mask is a string of hexadecimal digits, representing a bitmask of data columns in little-endian order. The bit position in the column mask is based on the ordinal of the column in the metadata message for that table. This allows the applier to distinguish a null value that is the actual value of the column, from a null value that represents a column which could not be replicated from the source database.
externalSchemaId	String	The Schema ID. This will only be displayed if the Include external Schema ID header check box is selected. As the Schema ID changes whenever a DDL is performed on the source table, consumer applications can use this information to determine if the message schema has changed.
transactionEventCounter	Long	The sequence number of the current operation in the transaction. This can be used to determine the order of operations within a transaction.
transactionLastEvent	Boolean	"True" indicates that it is the final record in the transaction whereas "False" indicates that not all of the records have been processed.
data	Structure	The data of the table record
{columns}		The column names and values in the current record.
beforeData	Structure	The data of the table record, before the change
{columns}		The column names and values, before the change. Applicable to UPDATE operation.

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