Step 2: Creating Links

Scenario

Before migrating a MySQL database to DWS, create the following two links:

• MySQL link: used to connect to an RDS for MySQL DB instance
• DWS link: used to connect to a DWS cluster

Prerequisites

• You have an RDS for MySQL DB instance and have obtained the name, username, and password for accessing the MySQL database. In addition, you have the read, write, and delete permissions for the MySQL database.
• You have a DWS cluster and have obtained the name, username, and password for accessing the DWS database. In addition, you have the read, write, and delete permissions for the DWS database.
• You have uploaded the MySQL database driver by referring to Managing Drivers.

Creating a MySQL Link

1. In the left navigation pane, choose Cluster Management. Locate the cdm-aff1 cluster created in Step 1: Creating a Cluster.
2. Click Job Management in the Operation column of the CDM cluster. On the displayed page, click the Links tab and then Create Link. The Select Connector page is displayed.
   Figure 1 Selecting a connector
   

3. Select RDS for MySQL and click Next to set the link parameters.
   Figure 2 Creating a MySQL link
   

   Click Show Advanced Attributes to view more optional parameters. For details, see Link to an RDS for MySQL/MySQL Database. Retain the default values of the optional parameters and configure the mandatory parameters according to Table 1.

   Table 1 MySQL link parameters

   Parameter	Description	Example Value
   Name	Unique link name	mysqllink
   Database Server	IP address or domain name of the MySQL database server	-
   Port	MySQL database port	3306
   Database Name	Name of the MySQL database	sqoop
   Username	User who has the read, write, and delete permissions on the MySQL database	admin
   Password	Password of the user	-
   Use Local API	Whether to use the local API of the database for acceleration. (The system attempts to enable the local_infile system variable of the MySQL database.)	Yes
   Use Agent	Whether to extract data from the data source through an agent	No
   local_infile Character Set	When using local_infile to import data to MySQL, you can configure the encoding format.	utf8
   Driver Version	Before connecting CDM to a relational database, you need to upload the JDK 8 .jar driver of the relational database. Download the MySQL driver 5.1.48 from https://downloads.mysql.com/archives/c-j/, obtain mysql-connector-java-5.1.48.jar, and upload it.	-

4. Click Test to check whether the parameters are correctly configured. If the test is successful, click Save to create the link and return to the Links page.
   Figure 3 Created MySQL link
   

Creating a DWS Link

1. Click Job Management in the Operation column of the CDM cluster. On the displayed page, click the Links tab and then Create Link. The Select Connector page is displayed.
   Figure 4 Selecting a connector
   

2. Select Data Warehouse Service and click Next to configure parameters for the DWS link.
   Figure 5 Creating a DWS link
   
   Click Show Advanced Attributes and set optional parameters. For details, see Link to Relational Databases. Table 2 lists the mandatory parameters. Retain the default values of optional parameters.

   Table 2 DWS link parameters

   Parameter	Description	Example Value
   Name	Unique link name	dwslink
   Database Server	IP address or domain name of the DWS database server	-
   Port	DWS database port	8000
   Database Name	Name of the DWS database	db_demo
   Username	User who has the read, write, and delete permissions on the DWS database	dbadmin
   Password	Password of the user	-
   Use Agent	Whether to extract data from the data source through an agent	No

3. Click Test to check whether the parameters are correctly configured. If the test is successful, click Save to create the link and return to the Links page.
   Figure 6 Created DWS link