AWS DMS通过在源和目标数据库之间运行任意数量的复制实例来实现DDL复制。每个复制实例都可以自行运行，因此可以同时进行许多DDL操作。复制实例会定期检查源和目标数据库的元数据以查看所有新的DDL更改，并将这些更改应用于目标数据库。

以下是通过AWS DMS实现DDL复制的示例代码：

1.创建一个DMS复制实例：

aws dms create-replication-instance \
--replication-instance-identifier my-dms-instance \
--allocated-storage 50 \
--engine-version 3.1.3 \
--vpc-security-group-ids sg-xxxxxx \
--availability-zone us-west-2a \
--replication-instance-class dms.t2.micro

2.创建源和目标端点：

aws dms create-endpoint \
--endpoint-identifier my-source-endpoint \
--endpoint-type source \
--engine-name mysql \
--password secret \
--server-name my-source-database.example.com \
--username admin

aws dms create-endpoint \
--endpoint-identifier my-target-endpoint \
--endpoint-type target \
--engine-name mysql \
--password secret \
--server-name my-target-database.example.com \
--username admin

3.创建复制任务：

aws dms create-replication-task \
--replication-task-identifier my-replication-task \
--source-endpoint-arn arn:aws:dms:us-west-2:xxxxxxxxxxxx:endpoint:my-source-endpoint \
--target-endpoint-arn arn:aws:dms:us-west-2:xxxxxxxxxxxx:endpoint:my-target-endpoint \
--replication-instance-arn arn:aws:dms:us-west-2:xxxxxxxxxxxx:rep:my-dms-instance \
--migration-type full-load-and-cdc \
--table-mappings file://table-mappings.json

4.为每个表指定DDL复制设置：

{
  "rules": [
    {
      "rule-type": "selection",
      "rule-id": "1",
      "rule-name": "1",
      "object-locator": {
        "schema-name": "mydb",
        "table-name": "orders"
      },
      "rule-action": "include",
      "filters": []
    },
    {
      "rule-type": "transformation",
      "rule-id": "2",
      "rule-name": "2",
      "rule-action": "modify",
      "metadata:modified-data": "{\"tablename\":\"orders\",\"tempfld\":\"_TEMPKEY\"}",
      "filters":