Fix NULL default value schema describing in sqlite.

* When getting schema for table column with DEFAULT NULL, populate
  returned object with null rather than string literal 'NULL'.
* Fixes #5051

lib/dialects/sqlite/query.js

@@ -178,7 +178,7 @@ Query.prototype.run = function(sql, parameters) {
                     result[_result.name] = {
                     result[_result.name] = {
                       type: _result.type,
                       type: _result.type,
                       allowNull: (_result.notnull === 0),
                       allowNull: (_result.notnull === 0),
-                      defaultValue: _result.dflt_value,
+                      defaultValue: (_result.dflt_value === 'NULL' ? null : _result.dflt_value),
                       primaryKey : (_result.pk === 1)
                       primaryKey : (_result.pk === 1)
                     };
                     };
 
 

test/integration/query-interface.test.js

@@ -150,6 +150,10 @@ describe(Support.getTestDialectTeaser('QueryInterface'), function() {
       var self = this;
       var self = this;
       var Users = self.sequelize.define('_Users', {
       var Users = self.sequelize.define('_Users', {
         username: DataTypes.STRING,
         username: DataTypes.STRING,
+        city: {
+            type: DataTypes.STRING,
+            defaultValue: null
+        },
         isAdmin: DataTypes.BOOLEAN,
         isAdmin: DataTypes.BOOLEAN,
         enumVals: DataTypes.ENUM('hello', 'world')
         enumVals: DataTypes.ENUM('hello', 'world')
       }, { freezeTableName: true });
       }, { freezeTableName: true });
@@ -161,6 +165,7 @@ describe(Support.getTestDialectTeaser('QueryInterface'), function() {
 
 
           var id = metadata.id;
           var id = metadata.id;
           var username = metadata.username;
           var username = metadata.username;
+          var city = metadata.city;
           var isAdmin = metadata.isAdmin;
           var isAdmin = metadata.isAdmin;
           var enumVals = metadata.enumVals;
           var enumVals = metadata.enumVals;
 
 
@@ -179,6 +184,12 @@ describe(Support.getTestDialectTeaser('QueryInterface'), function() {
           expect(username.allowNull).to.be.true;
           expect(username.allowNull).to.be.true;
           expect(username.defaultValue).to.be.null;
           expect(username.defaultValue).to.be.null;
 
 
+          switch (dialect) {
+            case 'sqlite':
+              expect(city.defaultValue).to.be.null;
+              break;
+          }
+
           assertVal = 'TINYINT(1)';
           assertVal = 'TINYINT(1)';
           switch (dialect) {
           switch (dialect) {
             case 'postgres':
             case 'postgres':