Support for dropping tables with constraints

lib/dialects/mysql/query-generator.js

@@ -496,6 +496,16 @@ module.exports = (function() {
       return fields
     },
 
+    enableForeignKeyConstraintsQuery: function() {
+      var sql = "SET FOREIGN_KEY_CHECKS = 1;"
+      return Utils._.template(sql, {})
+    },
+
+    disableForeignKeyConstraintsQuery: function() {
+      var sql = "SET FOREIGN_KEY_CHECKS = 0;"
+      return Utils._.template(sql, {})
+    },
+
     addQuotes: function(s, quoteChar) {
       return Utils.addTicks(s, quoteChar)
     },

lib/dialects/postgres/query-generator.js

@@ -78,7 +78,7 @@ module.exports = (function() {
 
     dropTableQuery: function(tableName, options) {
       options = options || {}
-      var query = "DROP TABLE IF EXISTS <%= table %>;"
+      var query = "DROP TABLE IF EXISTS <%= table %> CASCADE;"
       return Utils._.template(query)({
         table: QueryGenerator.addQuotes(tableName)
       })
@@ -602,8 +602,16 @@ module.exports = (function() {
       return fields
     },
 
+    enableForeignKeyConstraintsQuery: function() {
+      return false // not supported by dialect
+    },
+
+    disableForeignKeyConstraintsQuery: function() {
+      return false // not supported by dialect
+    },
+
     databaseConnectionUri: function(config) {
-      var template = '<%= protocol %>://<%= user %>:<%= password %>@<%= host %><% if(port) { %>:<%= port %><% } %>/<%= database %>';
+      var template = '<%= protocol %>://<%= user %>:<%= password %>@<%= host %><% if(port) { %>:<%= port %><% } %>/<%= database %>'
 
       return Utils._.template(template)({
         user:     encodeURIComponent(config.username),

lib/dialects/query-generator.js

@@ -229,7 +229,22 @@ module.exports = (function() {
     */
     findAutoIncrementField: function(factory) {
       throwMethodUndefined('findAutoIncrementField')
+    },
+
+    /*
+      Globally enable foreign key constraints
+    */
+    enableForeignKeyConstraintsQuery: function() {
+      throwMethodUndefined('enableForeignKeyConstraintsQuery')
+    },
+
+    /*
+      Globally disable foreign key constraints
+    */
+    disableForeignKeyConstraintsQuery: function() {
+      throwMethodUndefined('disableForeignKeyConstraintsQuery')
     }
+
   }
 
   var throwMethodUndefined = function(methodName) {

lib/dialects/sqlite/query-generator.js

@@ -265,6 +265,16 @@ module.exports = (function() {
       return fields
     },
 
+    enableForeignKeyConstraintsQuery: function() {
+      var sql = "PRAGMA foreign_keys = ON;"
+      return Utils._.template(sql, {})
+    },
+
+    disableForeignKeyConstraintsQuery: function() {
+      var sql = "PRAGMA foreign_keys = OFF;"
+      return Utils._.template(sql, {})
+    },
+
     hashToWhereConditions: function(hash) {
       for (var key in hash) {
         if (hash.hasOwnProperty(key)) {

lib/query-interface.js

@@ -91,11 +91,17 @@ module.exports = (function() {
       var chainer = new Utils.QueryChainer()
 
       self.showAllTables().success(function(tableNames) {
+
+        chainer.add(self, 'disableForeignKeyConstraints', [])
+
         tableNames.forEach(function(tableName) {
-          chainer.add(self.dropTable(tableName))
+          chainer.add(self, 'dropTable', [tableName])
         })
+
+        chainer.add(self, 'enableForeignKeyConstraints', [])
+
         chainer
-          .run()
+          .runSerially()
           .success(function() {
             self.emit('dropAllTables', null)
             emitter.emit('success', null)
@@ -313,6 +319,30 @@ module.exports = (function() {
     }).run()
   }
 
+  QueryInterface.prototype.enableForeignKeyConstraints = function() {
+    var sql = this.QueryGenerator.enableForeignKeyConstraintsQuery()
+    if(sql) {
+      return queryAndEmit.call(this, sql, 'enableForeignKeyConstraints')
+    } else {
+      return new Utils.CustomEventEmitter(function(emitter) {
+        this.emit('enableForeignKeyConstraints', null)
+        emitter.emit('success')
+      }).run()
+    }
+  }
+
+  QueryInterface.prototype.disableForeignKeyConstraints = function() {
+    var sql = this.QueryGenerator.disableForeignKeyConstraintsQuery()
+    if(sql){
+      return queryAndEmit.call(this, sql, 'disableForeignKeyConstraints')
+    } else {
+      return new Utils.CustomEventEmitter(function(emitter) {
+        this.emit('disableForeignKeyConstraints', null)
+        emitter.emit('success')
+      }).run()
+    }
+  }
+
   // private
 
   var queryAndEmit = function(sqlOrQueryParams, methodName, options, emitter) {

spec-jasmine/postgres/query-generator.spec.js

@@ -96,11 +96,11 @@ describe('QueryGenerator', function() {
     dropTableQuery: [
       {
         arguments: ['myTable'],
-        expectation: "DROP TABLE IF EXISTS \"myTable\";"
+        expectation: "DROP TABLE IF EXISTS \"myTable\" CASCADE;"
       },
       {
         arguments: ['mySchema.myTable'],
-        expectation: "DROP TABLE IF EXISTS \"mySchema\".\"myTable\";"
+        expectation: "DROP TABLE IF EXISTS \"mySchema\".\"myTable\" CASCADE;"
       }
     ],