ADO数据库表布尔列 [英] ADO Database Table Boolean Column

问题描述

我在使用ADO时遇到了麻烦。我已经部署了一个使用Access的数据库应用程序。随着不同版本的发布，数据库表具有不同的字段，一些添加了其他字段，等等。我无法使用的是如何在数据库中添加BOOLEAN字段。

I am having a bit of trouble with ADO. I have deployed a database application, which uses Access. With the release of different versions database tables have different fields, some added others deleted etc. What I can't get to work is how to add a BOOLEAN field in the database.

出于升级目的，我将标准的SQL查询组件与如下所示的sql一起使用：

For upgrade purposes I use the standart sql query component with a sql that looks like this :

ALTER TABLE XXX ADD COLUMN YY BOOLEAN

但这适用于其他数据类型，例如VARCHAR，INTEGER，DOUBLE等，但不适用与BOOLEAN。我怀疑这是Access的错，因为它是布尔值，是/否，但是谁知道。

while this works for other data types, such as VARCHAR, INTEGER, DOUBLE etc, it does not with BOOLEAN. I suspect it's Access's fault with it's YES/NO thing for boolean, but who knows.

此外，如何使用TADOTable向表中添加字段？

Also how can I add fields to a table using TADOTable?

预先感谢。

推荐答案

在Microsoft Access SQL中，BIT列直接对应于是/否字段。如果您以后尝试将其转换为SQL Server，我会遇到一种奇怪的行为，我的建议是执行以下操作：

In Microsoft Access SQL, The BIT column directly corresponds to the YES/NO field. I have experienced an odd behavior with it if you attempt to convert this later to SQL Server, and my advise is to then do the following:

每次进行检查时，针对此字段，请记住语法为（FIELD<> 0）用于检查TRUE，以及（FIELD = 0）用于检查false。 SQL Server不了解TRUE / FALSE的概念，在访问时，该值返回-1和0，而在SQL Server中，该值返回1和0。

When EVER you do a check against this field, remember the syntax should be (FIELD <> 0) for checking TRUE, and (FIELD = 0) for checking false. SQL Server doesn't understand the concept of TRUE/FALSE, and in access the value returns -1 and 0, while in SQL Server the values are 1 and 0.

在访问中，如果您还将字段设置为非null，它将仅显示一个复选框。如果允许使用null，则它将显示0或-1或为空。

In access it will only render a check box if you also set the field to not null. If nulls are allowed, then it will display the 0 or -1 or empty.

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