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10.4.19. EnumToString Filter

The EnumToString filter translates ENUM datatypes within MySQL tables into their string equivalent within the THL.

Pre-configured filter name enumtostring
Classname com.continuent.tungsten.replicator.filter.EnumToStringFilter
Property prefix replicator.filter.enumtostring
Stage compatibility binlog-to-q
tpm Option compatibility --repl-svc-extractor-filters
Data compatibility Row events
Parameters
Parameter Type Default Description
user string ${replicator.global.extract.db.user} The username for the connection to the database for looking up column definitions
password string ${replicator.global.extract.db.password} The password for the connection to the database for looking up column definitions
url string jdbc:mysql:thin://${replicator.global.extract.db.host}:${replicator.global.extract.db.port}/${replicator.schema}?createDB=true JDBC URL of the database connection to use for looking up column definitions

The EnumToString filter should be used with heterogeneous replication to ensure that the data is represented as the string value, not the internal numerical representation.

In the THL output below, the table has a ENUM column, country:

mysql> describe salesadv;
+----------+--------------------------------------+------+-----+---------+----------------+
| Field    | Type                                 | Null | Key | Default | Extra          |
+----------+--------------------------------------+------+-----+---------+----------------+
| id       | int(11)                              | NO   | PRI | NULL    | auto_increment |
| country  | enum('US','UK','France','Australia') | YES  |     | NULL    |                |
| city     | int(11)                              | YES  |     | NULL    |                |
| salesman | set('Alan','Zachary')                | YES  |     | NULL    |                |
| value    | decimal(10,2)                        | YES  |     | NULL    |                |
+----------+--------------------------------------+------+-----+---------+----------------+

When extracted in the THL, the representation uses the internal value (for example, 1 for the first enumerated value). This can be seen in the THL output below.

SEQ# = 138 / FRAG# = 0 (last frag)
- TIME = 2013-08-01 19:09:35.0
- EPOCH# = 122
- EVENTID = mysql-bin.000012:0000000000021434;0
- SOURCEID = host31
- METADATA = [mysql_server_id=1;dbms_type=mysql;service=alpha;shard=test]
- TYPE = com.continuent.tungsten.replicator.event.ReplDBMSEvent
- OPTIONS = [foreign_key_checks = 1, unique_checks = 1]
- SQL(0) =
 - ACTION = INSERT
 - SCHEMA = test
 - TABLE = salesadv
 - ROW# = 0
  - COL(1: id) = 2
  - COL(2: country) = 1
  - COL(3: city) = 8374
  - COL(4: salesman) = 1
  - COL(5: value) = 35000.00

For the country column, the corresponding value in the THL is 1. With the EnumToString filter enabled, the value is expanded to the corresponding string value:

SEQ# = 121 / FRAG# = 0 (last frag)
- TIME = 2013-08-01 19:05:14.0
- EPOCH# = 102
- EVENTID = mysql-bin.000012:0000000000018866;0
- SOURCEID = host31
- METADATA = [mysql_server_id=1;dbms_type=mysql;service=alpha;shard=test]
- TYPE = com.continuent.tungsten.replicator.event.ReplDBMSEvent
- OPTIONS = [foreign_key_checks = 1, unique_checks = 1]
- SQL(0) =
 - ACTION = INSERT
 - SCHEMA = test
 - TABLE = salesadv
 - ROW# = 0
  - COL(1: id) = 1
  - COL(2: country) = US
  - COL(3: city) = 8374
  - COL(4: salesman) = Alan
  - COL(5: value) = 35000.00

The information is critical when applying the data to a dataserver that is not aware of the table definition, such as when replicating to Oracle or MongoDB.

The examples here also show the Section 10.4.34, “SetToString Filter” and Section 10.4.8, “ColumnName Filter” filters.