bulkan/sequelize.md

## sequelize.md

      
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              sequelize.md
            
          
    Install

I'm sure you know know how to install packages but here is the command for the sake of completeness
npm install sequelize async
The first migration

First initilize the migrations structure
sequelize --init
Then create the initial migration, but dont edit this file as we will use it create the SequelizeMeta table.
sequelize -c initial
Create another migration
sequelize -c create-tables
Now dump your database without the data. With mysqldump
mysqldump -d --compact --compatible=mysql323 ${dbname}|egrep -v "(^SET|^/\*\!)".
We need to remove the `SET
Save this dump to the migrations folder and name it intial.sql
Edit the last migration that was created to look like;
var async = require('async')
  , fs = require('fs');

module.exports = {
  up: function(migration, DataTypes, done) {
    var db = migration.migrator.sequelize;

    async.waterfall([
      function(cb){
        fs.readFile(__dirname + '/initial.sql', function(err, data){
          if (err) throw err;
          cb(null, data.toString());
        });
      },

      function(initialSchema, cb){
        // need to split on ';' to get the individual CREATE TABLE sql
        // as db.query can execute on query at a time
        var tables = initialSchema.split(';');

        function createTable(tableSql, doneInsert){
          db.query(tableSql);
        }

        async.each(tables, createTable, cb);
      }
    ], done);
  },

  down: function(migration, DataTypes, done) {
    migration.showAllTables().success(function(tableNames){
    
      // Dont drop the SequelizeMeta table 
      var tables = tableNames.filter(function(name){
        return name.toLowerCase() !== 'sequelizemeta';
      });

      function dropTable(tableName, cb){
        migration.dropTable(tableName);
        cb();
      }

      async.each(tables, dropTable, done);
    });
  }
}

On the migrations up function we use async.waterfall to orchestrate a the async calls;

read in the initial.sql file
need to split the initial.sql and retrieve each CREATE TABLE queries as db.query can execute on query at a time
using async.each run each of these queries

On the migrations down function we just remove all tables that is not the SequelizeMeta table. For some reason migration.dropAllTables() remove this table and messes up the migrations. Not sure if this is the correct behavior.