Need to establish database connectivity in Drools

Question

Need to establish database connectivity in drools to get some data as and when required while executing the rules. How do I go about that?

You can write your own function in drl file to connect with DB — Abhijit Humbe, Jan 17 '18 at 02:26
@AbhijitHumbe It'll be great if you can share a sample code for connecting DB from drl file. — ankitom, Jan 17 '18 at 04:55
Does this answer your question? [Need to establish Database connectivity in DRL file](https://stackoverflow.com/questions/67498424/need-to-establish-database-connectivity-in-drl-file) — bjalexmdd, Oct 05 '21 at 16:37

score 0 · Answer 1 · answered Apr 03 '20 at 06:34

I have tried to establish Cassandra db connection from Drools file, It's working for me.

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

You can directly add the dependencies with below format, `import com.datastax.driver.core.Cluster` — Arul A M, Jan 14 '22 at 02:57

Abhijit Humbe · Accepted Answer · 2018-01-17T14:23:33.247

-1

Drools function will look like as:

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");

}

Take a look at sample project https://github.com/abhijithumbe/jbpm6Examples/tree/master/Drools_DBConnection

edited Jan 17 '18 at 14:23

answered Jan 17 '18 at 12:47

Abhijit Humbe

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Thanks @Abhijit. Your solution helped me. – ankitom Jan 18 '18 at 12:23
@Abhijit, do you know how to import data from excel into drl file. Here's the question: [link](https://stackoverflow.com/q/48418609/3628540) – ankitom Jan 24 '18 at 09:21

Need to establish database connectivity in Drools

2 Answers2