Metadata Column __hevo_database_name

__hevo_database_name is a Hevo-specific column added to the Destination table if you are loading data from multiple databases in the same Pipeline. In such cases, this column is useful to identify the database from which a particular row in the Destination originated.

Note: In case of PostgreSQL WAL mode and Oracle Sources , hevo_schema_name is added to identify the schema of the Source database.

This column is added only for the log-based Pipelines, and is based on a combination of the following settings that you define while creating the Pipeline:

Load All Databases
Merge Tables

For the Pipeline mode as Table, the database or schema name may be prefixed to the table name. Refer to the section below to know how to derive the database or schema name using a transformation script.

The table below is a quick reckoner for the scenarios when the hevo_database_name or hevo_schema_name column is added to the Destination table:

Source Name	Pipeline Mode	Load All Databases	Merge Tables	`hevo_database_name` added?	`hevo_schema_name` added?	Table Name
MySQL	Binlog	True	False	No	No	databasename_tablename
MySQL	Binlog	False	False	No	No	databasename.tablename
MySQL	Binlog	True	True	Yes	No	databasename.tablename
MySQL	Binlog	False	True	Yes	No	NA
MySQL	Table	NA	NA	No	No	databasename.tablename
Oracle	Redo Log	False: load all schema	True	No	Yes	NA
Oracle	Redo Log	False: load all schema	False	No	No	schemaname.tablename
Oracle	Redo Log	True: load all schema	False	No	No	schemaname.tablename
Oracle	Redo Log	True: load all schema	True	No	Yes	NA
Oracle	Table	NA	NA	No	No	schemaname.tablename
PostgreSQL	WAL	NA	True	No	Yes	NA
PostgreSQL	WAL	NA	False	No	No	tablename
PostgreSQL	Table	NA	False	No	No	tablename
MongoDB	Change stream	True	True	Yes	No	NA
MongoDB	Change stream	True	False	No	No	databasename.tablename
MongoDB	Change stream	False	True	Yes	No	NA
MongoDB	Change stream	False	False	No	No	databasename.tablename
MongoDB	Op Log	True	True	Yes	No	NA
MongoDB	Op Log	False	True	Yes	No	NA
MongoDB	Op Log	False	False	No	No	databasename.tablename
SQL Server	Table	NA	NA	No	No	schemaname.tablename

Deriving the Database or Schema Name

You can derive the database and/or schema name by using the following transformation script, as follows:

Script to derive the database name

FROM io.hevo.api import event
def transform(event):

  # Get properties FROM the event
  eventname = event.geteventname()
  properties = event.getproperties()
  res = eventname.rsplit('.', 1)
  # ADD a NEW field TO the event
  properties['database_name'] =res[0]

  return event

Sample output:

{
	"event_name": "leads.country",
	"properties": {
		"_id": "55a0f1d420a4d760b5fbefef",
		"Country Name": "Cocos Islands",
		"Language": "fil",
		"Database_name": "leads"
	}
}

Script to derive the schema name

from io.hevo.api import Event

def transform(event):
   # Get properties from the event
    eventName = event.getEventName()
    properties = event.getProperties()
    res = eventName.rsplit('.', 1)
    # Add a new field to the event
    properties['Schema_name'] =res[0]

    return event

Sample output:

{
	"event_name": "leads.country",
	"properties": {
		"_id": "55a0f1d420a4d760b5fc08cf",
		"Country Name": "France",
		"Language": "fr",
		"Schema_name": "leads"
	}
}

Last updated on May 30, 2023

Metadata Column __hevo_database_name

Deriving the Database or Schema Name

Script to derive the database name

Script to derive the schema name

Tell us what went wrong