source: trunk/grails-app/conf/DatabaseUpgrade.groovy @ 1352

import groovy.sql.Sql
import dbnp.studycapturing.Study

/**
 * A script to automatically perform database changes
 *
 * @Author      Jeroen Wesbeek
 * @Since       20101209
 *
 * Revision information:
 * $Rev: 1255 $
 * $Author: work@osx.eu $
 * $Date: 2010-12-09 16:49:30 +0000 (do, 09 dec 2010) $
 */
class DatabaseUpgrade {
        /**
         * handle database upgrades
         *
         * @param dataSource
         */
        public static void handleUpgrades(dataSource) {
                // get a sql instance
                groovy.sql.Sql sql = new groovy.sql.Sql(dataSource)

                // execute per-change check and upgrade code
                changeStudyDescription(sql)                     // r1245 / r1246
        }

        /**
         * execute database change r1245 / r1246 if required
         * @param sql
         */
        public static void changeStudyDescription(sql) {
                // check if we need to perform this upgrade
                if (sql.firstRow("SELECT count(*) as total FROM template_field WHERE templatefieldentity='dbnp.studycapturing.Study' AND templatefieldname='Description'").total > 0) {
                        // grom that we are performing the upgrade
                        "performing database upgrade: study description".grom()

                        // database upgrade required
                        try {
                                // get the template field id
                                def id = sql.firstRow("SELECT id FROM template_field WHERE templatefieldentity='dbnp.studycapturing.Study' AND templatefieldname='Description'").id

                                // iterate through all obsolete study descriptions
                                sql.eachRow("SELECT study_id, template_text_fields_elt as description FROM study_template_text_fields WHERE template_text_fields_idx='Description'") { row ->
                                        // migrate the template description to the study object itself
                                        // so we don't have to bother with sql injections, etc
                                        def study = Study.findById( row.study_id )
                                        study.setFieldValue('description', row.description)
                                        if (!(study.validate() && study.save())) {
                                                throw new Exception("could not save study with id ${row.study_id}")
                                        }
                                }

                                // delete all obsolete descriptions
                                sql.execute("DELETE FROM study_template_text_fields WHERE template_text_fields_idx='Description'")

                                // find all template id's where this field is used
                                sql.eachRow("SELECT DISTINCT template_fields_id, fields_idx FROM template_template_field WHERE template_field_id=${id}") { row ->
                                        // delete the template_template_field reference
                                        sql.execute("DELETE FROM template_template_field WHERE template_field_id=${id} AND template_fields_id=${row.template_fields_id}")

                                        // and lower the idx-es of the remaining fields
                                        sql.execute("UPDATE template_template_field SET fields_idx=fields_idx-1 WHERE fields_idx>${row.fields_idx} AND template_fields_id=${row.template_fields_id}")
                                }

                                // and delete the obsolete template field
                                sql.execute("DELETE FROM template_field WHERE id=${id}")
                        } catch (Exception e) {
                                "changeStudyDescription database upgrade failed: " + e.getMessage()
                        }
                }
        }
}