feat(belongsToMany): override unique constraint name with uniqueKey (#9914)

docs/associations.md

@@ -522,6 +522,11 @@ User.findAll({
   }]
 });
 ```
+Belongs-To-Many creates a unique key when primary key is not present on through model. This unique key name can be overridden using **uniqueKey** option.
+
+```js
+Project.belongsToMany(User, { through: UserProjects, uniqueKey: 'my_custom_unique' })
+```
 
 ## Naming strategy
 

lib/associations/belongs-to-many.js

@@ -252,7 +252,12 @@ class BelongsToMany extends Association {
     if (this.primaryKeyDeleted === true) {
       targetAttribute.primaryKey = sourceAttribute.primaryKey = true;
     } else if (this.through.unique !== false) {
-      const uniqueKey = [this.through.model.tableName, this.foreignKey, this.otherKey, 'unique'].join('_');
+      let uniqueKey;
+      if (typeof this.options.uniqueKey === 'string' && this.options.uniqueKey !== '') {
+        uniqueKey = this.options.uniqueKey;
+      } else {
+        uniqueKey = [this.through.model.tableName, this.foreignKey, this.otherKey, 'unique'].join('_');
+      }
       targetAttribute.unique = sourceAttribute.unique = uniqueKey;
     }
 

lib/model.js

@@ -3274,7 +3274,7 @@ class Model {
   setDataValue(key, value) {
     const originalValue = this._previousDataValues[key];
 
-    if ((!Utils.isPrimitive(value) && value !== null) || value !== originalValue) {
+    if (!Utils.isPrimitive(value) && value !== null || value !== originalValue) {
       this.changed(key, true);
     }
 
@@ -4269,6 +4269,7 @@ class Model {
    * @param {string}          [options.onDelete='SET NULL|CASCADE'] SET NULL if foreignKey allows nulls, CASCADE if otherwise
    * @param {string}          [options.onUpdate='CASCADE'] Sets 'ON UPDATE'
    * @param {boolean}         [options.constraints=true] Should on update and on delete constraints be enabled on the foreign key.
+   * @param {string}          [options.uniqueKey] The custom name for unique constraint.
    *
    * @returns {HasOne}
    *

test/integration/associations/belongs-to-many.test.js

@@ -2235,6 +2235,35 @@ describe(Support.getTestDialectTeaser('BelongsToMany'), () => {
         expect(ut2).to.have.length(1);
       });
     });
+
+    it('create custom unique identifier', function() {
+      this.UserTasksLong = this.sequelize.define('table_user_task_with_very_long_name', {
+        id_user_very_long_field: {
+          type: DataTypes.INTEGER(1)
+        },
+        id_task_very_long_field: {
+          type: DataTypes.INTEGER(1)
+        }
+      },
+      { tableName: 'table_user_task_with_very_long_name' }
+      );
+      this.User.belongsToMany(this.Task, {
+        as: 'MyTasks',
+        through: this.UserTasksLong,
+        foreignKey: 'id_user_very_long_field'
+      });
+      this.Task.belongsToMany(this.User, {
+        as: 'MyUsers',
+        through: this.UserTasksLong,
+        foreignKey: 'id_task_very_long_field',
+        uniqueKey: 'custom_user_group_unique'
+      });
+
+      return this.sequelize.sync({ force: true }).then(() => {
+        expect(this.Task.associations.MyUsers.through.model.rawAttributes.id_user_very_long_field.unique).to.equal('custom_user_group_unique');
+        expect(this.Task.associations.MyUsers.through.model.rawAttributes.id_task_very_long_field.unique).to.equal('custom_user_group_unique');
+      });
+    });
   });
 
   describe('Association options', () => {

test/unit/associations/belongs-to-many.test.js

@@ -593,6 +593,68 @@ describe(Support.getTestDialectTeaser('belongsToMany'), () => {
       expect(Group.associations.MyUsers.through.model.rawAttributes.GroupId.onUpdate).to.equal('SET NULL');
       expect(Group.associations.MyUsers.through.model.rawAttributes.GroupId.onDelete).to.equal('RESTRICT');
     });
+
+    it('generate unique identifier with very long length', function() {
+      const User = this.sequelize.define('User', {}, { tableName: 'table_user_with_very_long_name' }),
+        Group = this.sequelize.define('Group', {}, { tableName: 'table_group_with_very_long_name' }),
+        UserGroup = this.sequelize.define(
+          'GroupUser',
+          {
+            id_user_very_long_field: {
+              type: DataTypes.INTEGER(1)
+            },
+            id_group_very_long_field: {
+              type: DataTypes.INTEGER(1)
+            }
+          },
+          {tableName: 'table_user_group_with_very_long_name'}
+        );
+
+      User.belongsToMany(Group, { as: 'MyGroups', through: UserGroup, foreignKey: 'id_user_very_long_field' });
+      Group.belongsToMany(User, { as: 'MyUsers', through: UserGroup, foreignKey: 'id_group_very_long_field' });
+
+      expect(Group.associations.MyUsers.through.model === User.associations.MyGroups.through.model);
+      expect(Group.associations.MyUsers.through.model.rawAttributes.id_user_very_long_field.unique).to.have.lengthOf(92);
+      expect(Group.associations.MyUsers.through.model.rawAttributes.id_group_very_long_field.unique).to.have.lengthOf(92);
+      expect(Group.associations.MyUsers.through.model.rawAttributes.id_user_very_long_field.unique).to.equal('table_user_group_with_very_long_name_id_group_very_long_field_id_user_very_long_field_unique');
+      expect(Group.associations.MyUsers.through.model.rawAttributes.id_group_very_long_field.unique).to.equal('table_user_group_with_very_long_name_id_group_very_long_field_id_user_very_long_field_unique');
+    });
+
+    it('generate unique identifier with custom name', function() {
+      const User = this.sequelize.define('User', {}, { tableName: 'table_user_with_very_long_name' }),
+        Group = this.sequelize.define('Group', {}, { tableName: 'table_group_with_very_long_name' }),
+        UserGroup = this.sequelize.define(
+          'GroupUser',
+          {
+            id_user_very_long_field: {
+              type: DataTypes.INTEGER(1)
+            },
+            id_group_very_long_field: {
+              type: DataTypes.INTEGER(1)
+            }
+          },
+          {tableName: 'table_user_group_with_very_long_name'}
+        );
+
+      User.belongsToMany(Group, {
+        as: 'MyGroups',
+        through: UserGroup,
+        foreignKey: 'id_user_very_long_field',
+        uniqueKey: 'custom_user_group_unique'
+      });
+      Group.belongsToMany(User, {
+        as: 'MyUsers',
+        through: UserGroup,
+        foreignKey: 'id_group_very_long_field',
+        uniqueKey: 'custom_user_group_unique'
+      });
+
+      expect(Group.associations.MyUsers.through.model === User.associations.MyGroups.through.model);
+      expect(Group.associations.MyUsers.through.model.rawAttributes.id_user_very_long_field.unique).to.have.lengthOf(24);
+      expect(Group.associations.MyUsers.through.model.rawAttributes.id_group_very_long_field.unique).to.have.lengthOf(24);
+      expect(Group.associations.MyUsers.through.model.rawAttributes.id_user_very_long_field.unique).to.equal('custom_user_group_unique');
+      expect(Group.associations.MyUsers.through.model.rawAttributes.id_group_very_long_field.unique).to.equal('custom_user_group_unique');
+    });
   });
   describe('association hooks', () => {
     beforeEach(function() {