strapi/packages/strapi-generate-migrations/templates/migration.template

'use strict';

/**
 * New migration information
 *
 * Warning: this migration has been automatically generated. We strongly advise
 * you to manually verify those information.
 */

exports.up = function(connection, Promise) {
  <% var dropped = false; var onlyDrop = true;

    _.forEach(models, function (definition, model) {
      if (!_.isEmpty(_.get(models[model], 'up.drop'))) {
        dropped = true;
      }

      if (!_.isEmpty(_.get(models[model], 'up.others'))) {
        onlyDrop = false;
      }
    });

    if (dropped === true && onlyDrop === false) { %> return Promise.all([
      <% _.forEach(models, function(definition, model) { %><%= _.get(models[model], 'up.drop') %><% }); %>
    ]).then(function() {
      return Promise.all([
        <% _.forEach(models, function(definition, model) { %><%= _.get(models[model], 'up.others') %><% }); %>
      ]);
    });
  <% } else if (dropped === true && onlyDrop === true) { %>
    return Promise.all([
      <% _.forEach(models, function(definition, model) { %><%= _.get(models[model], 'up.drop') %><% }); %>
    ]);
  <% } else { %>
    return Promise.all([
      <% _.forEach(models, function(definition, model) { %><%= _.get(models[model], 'up.others') %><% }); %>
    ]);
  <% } %>
};

/**
 * How to rollback this migration
 *
 * Warning: this rollback has been automatically generated. We strongly advise
 * you to manually verify those information.
 */

exports.down = function(connection, Promise) {
  <% var dropped = false; var onlyDrop = true;

    _.forEach(models, function (definition, model) {
      if (!_.isEmpty(_.get(models[model], 'down.drop'))) {
        dropped = true;
      }

      if (!_.isEmpty(_.get(models[model], 'down.others'))) {
        onlyDrop = false;
      }
    });

    if (dropped === true && onlyDrop === false) { %>
    return Promise.all([
      <% _.forEach(models, function(definition, model) { %><%= _.get(models[model], 'down.drop') %><% }); %>
    ]).then(function() {
      return Promise.all([
        <% _.forEach(models, function(definition, model) { %><%= _.get(models[model], 'down.others') %><% }); %>
      ]);
    });
  <% } else if (dropped === true && onlyDrop === true) { %>
    return Promise.all([
      <% _.forEach(models, function(definition, model) { %><%= _.get(models[model], 'down.drop') %><% }); %>
    ]);
  <% } else { %>
    return Promise.all([
      <% _.forEach(models, function(definition, model) { %><%= _.get(models[model], 'down.others') %><% }); %>
    ]);
  <% } %>
};

/**
 * Migration's config
 */

exports.config = {

  /**
   * Transactions are an important feature of relational databases, as they allow
   * correct recovery from failures and keep a database consistent even in cases of
   * system failure. All queries within a transaction are executed on the same
   * database connection, and run the entire set of queries as a single unit of work.
   * Any failure will mean the database will rollback any queries executed on that
   * connection to the pre-transaction state.
   * By default, each migration is run inside a transaction.
   */

  transaction: true
};