Stored Procedure in H2 Database

Question

I am new to database and recently started writing test cases for H2 database. I want to know how to test a stored procedure in Eclipse. I have seen the following:

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Answer 1

There is no stored procedure and sql userdefined function in H2 database instead of that we use java methods and create a alias to refer that.We can call that methods using alias.

Below is a simple example:**

DROP ALIAS IF EXISTS MYFUNCTION;
CREATE ALIAS MYFUNCTION AS $$
String getTableContent(java.sql.Connection con) throws Exception {
    String resultValue=null;
    java.sql.ResultSet rs = con.createStatement().executeQuery(
    " SELECT * FROM TABLE_NAME");
       while(rs.next())
       {
        resultValue=rs.getString(1);
       }
    return resultValue;
}
$$;

Answer 2

Stored procedure in H2 database is same as java methods.So write java methods and can invoke using aliases.

Answer 3

You may have overlooked the examples in src/test/org/h2/samples/Function.java. Here's a related example:

Connection conn = DriverManager.getConnection("jdbc:h2:mem:", "sa", "");
Statement st = conn.createStatement();
st.execute("CREATE ALIAS getVersion FOR \"org.h2.engine.Constants.getVersion\"");
ResultSet rs;
rs = st.executeQuery("CALL getVersion()");
if (rs.next()) System.out.println("Version: " + rs.getString(1));

Console: Version: 1.4.191

Addendum: The feature is not limited to functions; aliased methods can execute arbitrary Java code. For example, the query() method defined in Function.java may be aliased and called as shown below:

Connection conn = DriverManager.getConnection("jdbc:h2:mem:", "sa", "");
Statement st = conn.createStatement();
st.execute("CREATE ALIAS query FOR \"cli.Function.query\"");
rs = st.executeQuery("CALL query('SELECT NAME FROM INFORMATION_SCHEMA.USERS')");
while (rs.next()) {
    System.out.println("User: " + rs.getString(1));
}

Console: User: SA

Note that cli.Function.query is a copy of org.h2.samples.Function.query.

Answer 4

Below is the way we used to implemented in our project. It might be helpful :)

package com.procedures;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class CRITICAL_ACTIONS {

    public static final int SAVE_ACTION(Connection connection) throws SQLException {
        try {
            Statement statement = connection.createStatement();
            return statement.executeUpdate("INSERT INTO SCHEMA1.CRITICAL_ACTIONS(COLLEAGUE_ID,JOURNEY_ID,TYPE,PRODUCT,DESCRIPTION,META_DATA,STATUS) values('12345',11111111,'ABC','Lloyds','hellow','hello','START')");
        } finally {
            //connection.close();
        }
    }

    public static final ResultSet FETCH_ACTION(Connection connection) throws SQLException {
        try {
            Statement statement = connection.createStatement();
            return statement.executeQuery("SELECT * FROM SCHEMA1.CRITICAL_ACTIONS");
        }finally {
            connection.close();
        }
    }


}

Calling H2 Java Stored-procedure in Java :-

    jdbcTemplate.update("CREATE ALIAS SAVE_ACTION FOR \"com.procedures.CRITICAL_ACTIONS.SAVE_ACTION\"");
    jdbcTemplate.update("CREATE ALIAS FETCH_ACTION FOR \"com.procedures.CRITICAL_ACTIONS.FETCH_ACTION\"");

    jdbcTemplate.getDataSource().getConnection().createStatement().execute("call SAVE_ACTION()");