Question

I’m checking the size of my database(when I check the used database size I found it’s in floating value) : I’m using this piece of code :

 Public class DBSize{

 private float dbSize;

    public float databaseSize(Float dbSize,String dataSize,String indexsize){
        String apps="apps";  // It's my DB name
        String query_data = "select table_schema,SUM(data_length+index_length)/1024/1024 AS total_mb,SUM(data_length)/1024/1024 AS data_mb,SUM(index_length)/1024/1024 AS index_mb,COUNT(*) AS tables,CURDATE() AS today FROM information_schema.tables where table_schema='"+apps+"' GROUP BY table_schema ORDER BY table_schema;";
        try {
            connection = getConnection();
            stmt = connection.createStatement();
            ResultSet rs=stmt.executeQuery(query_data);
            if(rs.next())      //as I'm selecting a particular database's information
            this.dbSize=rs.getFloat(2);
            this.dataSize=rs.getString(3);
            this.indexSize=rs.getString(4);

            System.out.println("DB Size : "+this.dbSize);           
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        finally
        {
            try {
                if(stmt != null)
                    stmt.close();
                if(connection != null)
                    connection.close();
                } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        return dbSize;

    }

public float getDbSize(){
        return dbSize;
    }
}

rs is getting null value(don’t know whether unable to fetch the value from database or not),even I have used String type the function but also getting the null value,

Any inputs …that where I’m going wrong 🙁 🙁

Answer 1

Keep those three statements of assignment after if inside a block otherwise only first statement will get executed if the condidion rs.next() evaluates to true and next 2 statements will always execute even if the condidion rs.next() evaluates to false which may cause some exception

if(rs.next()){     
   this.dbSize=rs.getFloat(2);
   this.dataSize=rs.getString(3);
   this.indexSize=rs.getString(4);
}