How to query exist data before migration

[rkmax]

Example

I need add a new notNull: true column, but the table has rows. so

1. I need get current the data from the table
2. add the new column with the notNull: true property
3. insert updated records
4. update the column definition with notNull: true

dbm = dbm || require('db-migrate');
var type = dbm.dataType,
    async = require('async');

exports.up = function(db, callback) {

  async.series([
      db.addColumn.bind(db, 'users', 'email', {
        type: type.STRING
      }),
      // get the current and update
      db.changeColumn.bind(db, 'users', 'email', {
        type: type.STRING,
        notNull: true
      }),            
  ], callback);
};

exports.down = function(db, callback) {
  db.removeColumn('users', 'email', callback);
};

How i can get the current data?

[wzrdtales]

Data operations are not exactly a part of the migrations. This more or less belongs to seeding data.

Yet you can't select data, but there are features which are going to be introduced within v0.10.x
I reference here to this:
#215

and this:
#230

So currently you can't do this via any method which is intended to do this. But this doesn't mean it is impossible.

You need to fallback to runSql and select your data by native queries, but why you don't just add a defaultValue to your definition. With a defaultValue you can set notNull to true unless it is keyed with unique or primary.

[rkmax]

@wzrdtales yes, The new column is for unique values

[wzrdtales]

Then you need to fallback to runSql right now.

[rkmax]

Thanks that was what I did?

For example

exports.up = function (db, callback) {
  async.series([
    db.addColumn.bind(db, 'users', 'email', {
      type: type.STRING
    }),
    function (cb) {

      return db.runSql('SELECT * FROM users', [], function (err, results) {
        var inserts = [];
        results.rows.forEach(function (row) {
          inserts.push(db.runSql.bind(
              db, 'UPDATE users SET email = ? WHERE id = ?', [row.username + '@example.com', row.id]
          ));
        });
        async.series(inserts, cb);
      });
    },
    db.changeColumn.bind(db, 'users', 'email', {
      type: type.STRING,
      notNull: true
    }),
    db.addIndex.bind(db, 'users', 'email_unique', ['email'], true),
    db.addIndex.bind(db, 'users', 'username_unique', ['username'], true)
  ], callback);
};

[wzrdtales]

That is probably a solution, if this works for you.