需要在 Drools 中建立数据库连接

Question

需要在 drools 中建立数据库连接，以便在执行规则时根据需要获取一些数据。我该怎么做？

Answer 1

Drools 函数将如下所示：

function String ConnectDB(String ConnectionClass,String url,String user, String password) {

Class.forName(ConnectionClass);
java.sql.Connection con = DriverManager.getConnection(url, user, password);
Statement st = con.createStatement();
ResultSet rs = st.executeQuery("select * from Employee where employee_id=199");
rs.first();  return rs.getString("employee_name");

}

查看示例项目https://github.com/abhijithumbe/jbpm6Examples/tree/master/Drools_DBConnection

Answer 2

我尝试从 Drools 文件建立 Cassandra 数据库连接，它对我有用。

import com.datastax.driver.core.Cluster
import com.datastax.driver.core.Session     
import com.datastax.driver.core.ResultSet;     

function String ConnectDBase(String query) {
Session session;
Cluster cluster;
Cluster.Builder builder = Cluster.builder().
                  withoutJMXReporting().
                  addContactPoints("127.0.0.1");
         cluster = builder.build();
         session = cluster.connect("droolstest");
         System.out.println("---------Execute Creation query-----------");
         session.execute(query);
         return "Table Created";
}

rule "DB Connectio

n rule"
    when
        //Write your code
    then
        String query = "CREATE TABLE emp(emp_id int PRIMARY KEY, "
                   + "emp_name text, "
                   + "emp_city text, "
                   + "emp_sal varint, "
                   + "emp_phone varint );";
    System.out.println(ConnectDBase(query));
end

需要在 Drools 中建立数据库连接

Need to establish database connectivity in Drools

database

drools

kie