sql - SimpleMembership 制約を削除できませんでした

Question

実行時:

ALTER TABLE [dbo].[webpages_UsersInRoles] DROP CONSTRAINT [FK_dbo.webpages_UsersInRoles_dbo.webpages_Membership_UserId]

エラーが表示されます:

'FK_dbo.webpages_UsersInRoles_dbo.webpages_Membership_UserId' is not a constraint.
Could not drop constraint. See previous errors.

これは私のwebpages_UsersInRolesテーブルです：

CREATE TABLE [dbo].[webpages_UsersInRoles] (
    [UserId] INT NOT NULL,
    [RoleId] INT NOT NULL,
    PRIMARY KEY CLUSTERED ([UserId] ASC, [RoleId] ASC),
    CONSTRAINT [fk_UserId] FOREIGN KEY ([UserId]) REFERENCES [dbo].[UserProfile] ([UserId]),
    CONSTRAINT [fk_RoleId] FOREIGN KEY ([RoleId]) REFERENCES [dbo].[webpages_Roles] ([RoleId])
);

この回答に従ってやってみましたが、うまくいきませんでした。