Fix issues found while attempting to use migration functionality with postgres.

lib/dialects/postgres/query-generator.js

@@ -92,6 +92,11 @@ module.exports = (function() {
       return "SELECT table_name FROM information_schema.tables WHERE table_schema = 'public';"
     },
 
+    describeTableQuery: function(tableName) {
+      var query = 'SELECT column_name as "Field", column_default as "Default", is_nullable as "Null", data_type as "Type" FROM information_schema.columns WHERE table_name = <%= table %>;'
+      return Utils._.template(query)({ table: addQuotes(tableName, "'") })
+    },
+
     addColumnQuery: function(tableName, attributes) {
       var query      = "ALTER TABLE <%= tableName %> ADD COLUMN <%= attributes %>;"
         , attrString = Utils._.map(attributes, function(definition, attributeName) {
@@ -110,15 +115,30 @@ module.exports = (function() {
     },
 
     changeColumnQuery: function(tableName, attributes) {
-      var query      = "ALTER TABLE <%= tableName %> ALTER COLUMN <%= attributes %>;"
-      var attrString = Utils._.map(attributes, function(definition, attributeName) {
-        return Utils._.template('<%= attributeName %> <%= attributeName %> <%= definition %>')({
-          attributeName: addQuotes(attributeName),
-          definition: pgDataTypeMapping(tableName, attributeName, definition)
+      var query = "ALTER TABLE <%= tableName %> ALTER COLUMN <%= query %>;"
+
+      var sql = Utils._.map(attributes, function(definition, attributeName) {
+        var attrSql = ''
+        if (definition.indexOf('NOT NULL') > 0) {
+          attrSql += Utils._.template(query)({
+            tableName: addQuotes(tableName),
+            query: addQuotes(attributeName) + ' SET NOT NULL'
+          })
+          definition = definition.replace('NOT NULL', '').trim()
+        } else {
+          attrSql += Utils._.template(query)({
+            tableName: addQuotes(tableName),
+            query: addQuotes(attributeName) + ' DROP NOT NULL'
+          })
+        }
+        attrSql += Utils._.template(query)({
+          tableName: addQuotes(tableName),
+          query: addQuotes(attributeName) + ' TYPE ' + definition
         })
-      }).join(', ')
+        return attrSql;
+      }).join('')
 
-      return Utils._.template(query)({ tableName: addQuotes(tableName), attributes: attrString })
+      return sql
     },
 
     renameColumnQuery: function(tableName, attrBefore, attributes) {
@@ -272,7 +292,8 @@ module.exports = (function() {
     },
 
     showIndexQuery: function(tableName, options) {
-      throw new Error('showIndexQuery is not implemented for PostgreSQL')
+      var query = "SELECT relname FROM pg_class WHERE oid IN ( SELECT indexrelid FROM pg_index, pg_class WHERE pg_class.relname='<%= tableName %>' AND pg_class.oid=pg_index.indrelid);"
+      return Utils._.template(query)({ tableName: tableName });
     },
 
     removeIndexQuery: function(tableName, indexNameOrAttributes) {

lib/dialects/postgres/query.js

@@ -33,6 +33,8 @@ module.exports = (function() {
 
       if (self.sql.indexOf('SELECT table_name FROM information_schema.tables') == 0) {
         results.push(Utils._.values(row))
+      } else if (self.sql.indexOf('SELECT relname FROM pg_class WHERE oid IN') == 0) {
+        results.push(Utils._.values(row))
       } else if (self.sql.indexOf('SELECT') == 0) {
         // transform results into real model instances
         // return the first real model instance if options.plain is set (e.g. Model.find)

lib/query-interface.js

@@ -80,7 +80,13 @@ module.exports = (function() {
     var self = this
 
     return new Utils.CustomEventEmitter(function(emitter) {
-      self.sequelize.query('DESCRIBE `' + tableName + '`;', null, { raw: true }).success(function(data) {
+      var sql;
+      if (self.QueryGenerator.describeTableQuery) {
+        sql = self.QueryGenerator.describeTableQuery(tableName)
+      } else {
+        sql = 'DESCRIBE `' + tableName + '`;'
+      }
+      self.sequelize.query(sql, null, { raw: true }).success(function(data) {
         emitter.emit('success', data)
       }).error(function(err) {
         emitter.emit('failure', err)