将用户输入与已建立的表的列进行比较

Question

我有一个用户输入进入数据库以与表的列进行比较。我在比较另一列的列上发现了大量信息，但似乎无法正常工作。

这是我的代码：

CREATE Procedure Check_Previous_Passwords
    @ua_pk uniqueidentifier,
    @IncomingPassword varchar(25)
AS
    DECLARE @TempTable TABLE (Passwords varchar(25))

    INSERT INTO @TempTable
    SELECT *
    FROM User_Passwords
    WHERE ua_fk = @ua_pk

    IF @IncomingPassword = @TempTable.Passwords
        --Then do stuff

GO

我很确定这是我完全忽略的事情。谢谢！

Answer 1

您不应该以明文形式传递密码。

我也不明白您为什么要创建临时表。你可以这样做：

if (exists (select 1 from User_Passwords up where up.ua_fk = @ua_pk and @IncomingPassword = up.Password))
begin
. . .
end;
else
begin
. . .
end;

Answer 2

CREATE Procedure Check_Previous_Passwords
    @ua_pk uniqueidentifier,
    @IncomingPassword varchar(25)
AS
    DECLARE @Temp VARCHAR(25)

    SET @Temp = (SELECT TOP 1 Password 
                 FROM User_Passwords 
                 WHERE ua_fk = @ua_pk 
                 ORDER BY someDate DESC)


    IF @IncomingPassword = @Temp
        BEGIN
              SELECT 'You can't reuse the same PW'
        END
    ELSE
        BEGIN
              --do work
        END

GO

这只是检查最后一个密码以确保它不一样。如果要检查最后 N 个密码，我们可以使用 IN 子句或 EXISTS

CREATE Procedure Check_Previous_Passwords
    @ua_pk uniqueidentifier,
    @IncomingPassword varchar(25)
AS
    DECLARE @Temp VARCHAR(25)

    SET @Temp = (SELECT TOP 1 Password 
                 FROM User_Passwords 
                 WHERE ua_fk = @ua_pk 
                 ORDER BY someDate DESC)


    IF (EXISTS (SELECT 1 FROM User_Passwords up where up.ua_fk = @ua_pk and @IncomingPassword = up.Password))
        BEGIN
              SELECT 'You can't reuse the same PW'
        END
    ELSE
        BEGIN
              --do work... like an insert
        END

GO