DDL history
The attrep_ddl_history table contains a history of DDL changes that occurred in the source during replication to the target.
The DDL History table is currently supported with the following target endpoints only:
- Hadoop
- Hortonworks Data Platform
- Microsoft Azure HDInsight
- Amazon EMR
- Google Dataproc
- Microsoft Azure Databricks
-
Databricks on AWS
-
Databricks on Google Cloud
- Cloudera Data Platform (CDP) Private Cloud
A new record is inserted into the table whenever a supported DDL change occurs in the source. Multiple ALTER TABLE statements that occur during a task may be represented as a single row in the control table. The JSON buffer (see below) describes all the changes that occurred (e.g. ADD COLUMN A, DROP COLUMN B, ALTER COLUMN C).
For information on enabling the DDL History Control Table as well as its limitations, see Control tables.
When the Apply Changes task option is enabled, an entry is created for the base table (e.g. tblT1). If the Store Changes task option is also enabled, an additional entry is created for the CT table (e.g. tblT1__CT).
| Column | Type | Description |
|---|---|---|
|
SERVER_NAME |
STRING |
The name of the machine on which Qlik Replicate is installed. |
|
TASK_NAME |
STRING |
The name of the Qlik Replicate task. |
|
TABLE_OWNER |
STRING |
The source table schema or owner. |
|
TABLE_NAME |
STRING |
The source table name. If the table was renamed, this will be the table name before the change. |
|
CHANGE_SEQ |
STRING |
See Change_Seq in Using Change Tables. |
|
TIMESTAMP |
TIMESTAMP |
When the change occurred. |
|
TABLE_VERSION |
INTEGER |
Replicate assigns an internal version number to the table. The version number increases whenever a DDL change occurs in the source table. |
|
DDL_TYPE |
STRING |
CREATE_TABLE, DROP_TABLE, ALTER_TABLE, TRUNCATE_TABLE |
|
DETAILS |
CLOB |
JSON document describing the change(s) Example: {
"owner": "string",
"table": "string",
"tableNewName": "string",
"version": number,
"columns":
{
"col1":
{
"columnNewName": "string",
"action": "string",
"type":" string",
"length": number,
"precision": number,
"scale": number,
"primaryKeyPosition": number,
"nullable": boolean,
"ordinal": number
},
"col2":
{
…
}
}
}
where:
|