exp_101.htm

来自「oracle　DBA的资料」· HTM 代码 · 共 46 行

HTM

46 行

<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=gb2312">
<title>Ocp test </title>
</head>
<body bgcolor="white" text="black" link="blue" vlink="purple" alink="red">
<p><b><span style="font-size:22pt">Explaination 101: &nbsp;</span></b></p>

<span style="font-size:18pt">
	<p>
	The NOT NULL constraint can be defined only at the column level. It enforces that a value must be defined for this column such that the column may not be NULL for any row. <br>
	</p>

	<p>
	  Incorrect Answers <br>
	</p>

	<p>
	  A: The UNIQUE constraint enforces uniqueness on values in the constrained column. It can be defined not only at the column level. <br>
	</p>

	<p>
	  C: The CHECK constraint enforces that values added to the constrained column must be present in a static list of values permitted for the column. <br>
	</p>

	<p>
	  D: The PRIMARY KEY constraint stipulates that values in the constrained column(s) must be unique and not NULL. If the primary key applies to multiple columns, then the combination of values in the columns must be unique and not NULL. <br>
	</p>

	<p>
	  E: The FOREIGN KEY constraint enforces that only values in the primary key of a parent table may be included as values in the constrained column(s) of the child table. <br>
	</p>

	<p>
	  OCP Introduction to Oracle 9i: SQL Exam Guide, Jason Couchman, p. 227-232 <br>
	</p>

	<p>
	  Chapter 5: Creating Oracle Database Objects
	</p>

</span>

</body>
</html>

exp_101.htm - 源码说明

本页面展示了「oracle　DBA的资料」中的 exp_101.htm 源码文件，采用 HTM 编程语言编写，共 46 行代码。您可以在线阅读完整代码内容，也可以返回资源详情页下载完整源码包进行本地学习和开发。

虫虫开发者社区收录了大量与Oracle相关的技术资源，包括源代码、技术文档、电路图等，是电子工程师和嵌入式开发者的专业学习平台。

⌨️ 快捷键说明

复制代码Ctrl + C

搜索代码Ctrl + F

全屏模式F11

增大字号Ctrl + =

减小字号Ctrl + -

显示快捷键?