Complete the porting script framework

- Generalized to make porting easier by changing only the transform.js
file which is nothing but json.

Author: coditva

tools/port_script/index.js

@@ -1,6 +1,9 @@
 const mysql = require('mysql');
 const config = require('./config.js');
 const transform = require('./transform.js');
+const _ = require('lodash');
+
+const DEBUG = 1;
 
 // Connect to the source database
 const source = mysql .createConnection({
@@ -27,43 +30,117 @@ dest.connect(function(err) {
 });
 
 
-for (var item in transform) {
-  console.log(transform[item].table.old);
-  source.query('SELECT * FROM ' + transform[item].table.old + ';',
-    function(err, res, fields) {
-      if (err) { throw err; }
-      console.log('\nCopying table ' + transform[item].table.old);
-      for (var i in res) {
-        let query = 'INSERT INTO ';
-        query += transform[item].table.new;
-        query += ' (';
-
-        // Load fields in order
-        let values = '';
-        let count = 0;
-        for (var newField in transform[item].fields) {
-          if (count != 0) {
-            query += ', ';
-            values += ', ';
+_.forEach(transform, (rule) => {
+  let select_query = null;
+  if (rule.table.old.union) {
+    console.log('union');
+    select_query = 'SELECT * FROM ' + rule.table.old.union[0] + ' INNER JOIN (';
+
+    let count = 0;
+    _.forEach(rule.table.old.union, (table) => {
+
+      if (count == 0) {
+        console.log('hi');
+      } else if (count == 1) {
+        select_query += table;
+      } else {
+        select_query += ', ' + table;
+      }
+      count++;
+    });
+
+    select_query += ') ON (' + rule.table.old.on + ')';
+  } else {
+    select_query = 'SELECT * FROM ' + rule.table.old;
+  }
+  DEBUG && (select_query += ' LIMIT 5');
+  select_query += ';';
+  console.log(select_query);
+
+  // Run the query
+  source.query(select_query, function(err, tuples, fields) {
+
+    if (err) { throw err; }
+    console.log('\nCopying table ' + rule.table.new);
+
+    _.forEach(tuples, (tuple) => {
+
+      let query = 'INSERT INTO ';
+      query += rule.table.new;
+      query += ' (';
+
+      // Load fields in order
+      let values = '';
+      let count = 0;
+      _.forEach(rule.fields, (field, field_name) => {
+
+        // Add comma if not the first item
+        if (count != 0) {
+          query += ', ';
+          values += ', ';
+        }
+
+        // Add field name to query
+        query += field_name;
+
+        // TODO: Add various data cleaning techniques here
+        let attribute = field;
+
+        // check if there's a condition
+        if (attribute.if) {
+
+          if (condition_eval(attribute.if.condition, tuple)) {
+            values += '"' + attribute.if.pass.value + '"';
+          } else {
+            values += '"' + attribute.if.fail.value + '"';
           }
-          query += newField;
 
-          // Add various data cleaning techniques here
-          values += '"' + res[i][transform[item].fields[newField]] + '"';
+        } else {
+          values += '"' + tuple[field] + '"';
           count++;
         }
+      }); // end forEach(fields)
 
-        query += ') VALUES (' + values;
-        query += ');';
+      query += ') VALUES (' + values;
+      query += ');';
 
-        // Run the query
-        dest.query(query, function(err, ans) {
-          if (err) { throw err; }
-          else {
-            console.log(query);
-          }
-        });
-      }
+      // Run the query
+      DEBUG && console.log(query + '\n');
+      DEBUG || dest.query(query, function(err, ans) {
+        if (err) { throw err; }
+        else {
+          console.log(query);
+        }
+      });
+
+    }); // end of forEach(res)
+  });
+});
+
+function condition_eval(condition, data) {
+  if (condition.eval) {
+    let first = data[condition.eval.first_attribute] || condition.eval.first_value || null;
+    let second = data[condition.eval.second_attribute] || condition.eval.second_value || null;
+
+    switch (condition.eval.operator) {
+      case '==':
+      case '===':
+        if (first == second) {
+          return true;
+        } else {
+          return false;
+        }
+        break;
+      default:
+        throw 'Operator not supported';
     }
-  );
+  } else if (condition.or) {
+    // TODO: make this variable
+    return condition_eval(condition.or[0], data) || condition_eval(condition.or[1], data);
+  } else if (condition.and) {
+    // TODO: make this variable
+    return condition_eval(condition.or[0], data) && condition_eval(condition.or[1], data);
+  } else {
+    throw 'Could not find eval or a condition';
+  }
 }

tools/port_script/package.json

@@ -18,6 +18,7 @@
   },
   "homepage": "https://gist.github.com/3677845cf74d5018c7706701bb0a851c",
   "dependencies": {
+    "lodash": "^4.17.4",
     "mysql": "^2.14.1"
   }
 }

tools/port_script/transform.js

@@ -1,14 +1,39 @@
-
 module.exports = {
   0 : {
     table: {
-      old: 'student_info',
+      old: {
+        union: ['student_info', 'cgpa'],
+        on: 'student_info.login_id = cgpa.login_id'
+      },
       new: 'student'
     },
     fields: {
       id: 'login_id',
       studentName: 'student_name',
-      bitsId: 'id'
+      bitsId: 'id',
+      hostelPs: {
+        if: {
+          condition: {
+            or: [
+              { eval: { operator: '===', first_attribute: 'hostel', second_value: 'PS2' }, },
+              { eval: { operator: '===', first_attribute: 'hostel', second_value: 'THESIS' } },
+            ]
+          },
+          pass: { value: 1 },
+          fail: { value: 0 }
+        },
+      },
+      gender: 'gender',
+      bDay: 'bday',
+      phone: 'phone',
+      email: 'email',
+      address: 'address',
+      bloodGroup: 'bloodgroup',
+      cgpa: 'cgpa',
+      admit: 'admit',
+      parentName: 'father_name',
+      parentPhone: 'father_phone',
+      parentEmail: 'father_email'
     }
   }
 }