how-to-check-a-new-database.md

How to Check a New Database

JDBC Dependency

Add the JDBC driver dependency for the new database to pom.xml.

For example, the JDBC driver dependency for the MySQL is

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.33</version>
</dependency>

Collector

Then, create a new package in the src/main/java/collector directory, and create two classes in this package to extend Collector and DBClient.

Custom collector should have a String field NAME to represent the category of this database. IsoVista uses this field in config.properties to select the database for the history collector.

public static final String NAME = "MYSQL";

The collector needs to explicitly load the JDBC driver in the code to prevent conflicts between drivers.

static {
    try {
        Class.forName("com.mysql.cj.jdbc.Driver");
    } catch (ClassNotFoundException e) {
        throw new RuntimeException(e);
    }
}

There are 4 methods the custom collector need to implement:

• collect: Use DBClient and a thread pool to simulate multiple database client accesses to the database.
• crateTable: Use JDBC to create a database table for subsequent history collection.
• createVariables: Pre-insert the initial values of variables into the created database table.
• dropDatabase: After completing the history collection, delete the database table.

For details, please refer to src/main/java/collector/mysql/MySQLClient.java.

DBClient

DBClient uses JDBC to connect to the database and converts a read-write(or list-append) operation into SQL and executes it.

For example, the operation "write value 2 to variable 1" in SQL is

UPDATE [table] SET val=2 WHERE var=1;

The operation "read value 4 from variable 3"

SELECT val FROM dbtest.variables WHERE var=3;