Only One Axis of Headers Needed

Definition

For some (usually smaller) tables, it is easy to infer the relationship between cells with only a single axis of headers. And in fact, using both may be overly verbose for screen reader users.

Remediation Example

It is easy to discern that this table is describing the structure of a database, and readers of this sort of content will be able to infer that where and and are query operators, Employee, Project, and WorksOn are names of tables within the database, and the third column contains details about those tables. It is not necessary to add headers to describe these columns, and in fact it could be considered overly verbose.

5.13 Using relational algebra, create a view of all rooms in the Grosvenor Hotel, excluding price details. What are the advantages of this view?

The following tables form part of a database held in an RDBMS:

Employee (empNo, fName, lName, address, DOB, sex, position, deptNo)
Department (deptNo, deptName, mgrEmpNo)
Project (projNo, projName, deptNo)
WorksOn (empNo, projNo, dateWorked, hoursWorked)

where	Employee	contains employee details and empNo is the key.
	Department	contains department details and deptNo is the key. mgrEmpNo identifies the employee who is the manager of the department. There is only one manager for each department.
	Project	contains details of the projects in each department and the key is projNo (no two departments can run the same project).
and	WorksOn	contains details of the hours worked by employees on each project, and empNo/projNo/dateWorked form the key.

<p>
    <span class="number">5.13 </span>Using relational algebra, create a view of all rooms in the Grosvenor Hotel, excluding price details. What are the advantages of this view? 
</p>
<p>
    The following tables form part of a database held in an RDBMS: 
</p>
<ul class="ul_none">
    <li> 
    <p>
        <b>Employee (</b><b><span class="wol"><b>empNo</b></span></b><b>, fName, lName, address, DOB, sex, position, deptNo)</b> 
    </p>
    </li>
    <li> 
    <p>
        <b>Department (</b><b><span class="wol"><b>deptNo</b></span></b><b>, deptName, mgrEmpNo)</b> 
    </p>
    </li>
    <li> 
    <p>
        <b>Project (</b><b><span class="wol"><b>projNo</b></span></b><b>, projName, deptNo)</b> 
    </p>
    </li>
    <li> 
    <p>
        <b>WorksOn (</b><b><span class="wol"><b>empNo</b></span></b><b>,</b> <b><span class="wol"><b>projNo</b></span></b><b>,</b> <b><span class="wol"><b>dateWorked</b></span></b><b>, hoursWorked)</b> 
    </p>
    </li>
</ul>
<table class="largetable">
    <tbody>
        <tr>
            <td>where</td>
            <td><b>Employee</b></td>
            <td>contains employee details and <b>empNo</b> is the key.</td>
        </tr>
        <tr>
            <td />
            <td><b>Department</b></td>
            <td> contains department details and <b>deptNo</b> is the key. <b>mgrEmpNo</b> identifies the employee who is the manager of the department. There is only one manager for each department.</td>
        </tr>
        <tr>
            <td />
            <td><b>Project</b></td>
            <td>contains details of the projects in each department and the key is <b>projNo</b> (no two departments can run the same project).</td>
        </tr>
        <tr>
            <td>and</td>
            <td><b>WorksOn</b></td>
            <td>contains details of the hours worked by employees on each project, and <b>empNo/projNo/dateWorked</b> form the key.</td>
        </tr>
    </tbody>
</table>

Empty Cells Table Inside Table