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<document>
  <header>
    <title>Makumba Documentation - Validation Rules</title>
  </header>
  <body>
  
    <p>Validation rules are defined inside a data definition, and allow Makumba to automatically validated form data
    input.</p>
    <p>The general syntax of a validation rule definition is as follows:</p>
    <source>[validation rule name] : [validation rule] : [error message]</source>
    
    <section><title>Validation rule name</title>
    <p>The validation rule name is an identifier which should be unique. The exact usage is not yet specified, but
    it could be used in the future to centralise error messages or provide translations into other languages, etc.</p>
    </section>
    
    <section><title>Validation rule</title>
    <p>The validation rule specifies what should be validated, and can be one of the following</p>
    <source>[range validation | string length | regular expression | comparison]</source>
    
    <section id="range"><title>Number range rule</title>
    <p>The range definition rule applies for <code>Number</code> types, i.e. <em>int</em> and <em>real</em>. The
    [validation rule] is defined as:</p>
    <source>[fieldName]%range = [1..10]</source>
    <p>Using <code>?</code> allows to keep one parameter unbound, which will default to java.lang.Integer.MIN_VALUE
    and java.lang.Integer.MAX_VALUE, respectively, i.e. +/- 2<sup>31</sup>-1.</p>
    <p>To require that the age needs to be between 12 and 99:</p>
    <source>age%range = [12..99] : Age must be between 12 and 99!</source>
    <p>To define that we need to be at least 5 year old, but without any upper limit:</p>
    <source>age%range = [5..?] : Age must be at least 5!</source>
    </section>

    <section id="stringLength"><title>String length rule</title>
    <p>The length definition rule is very similar to the range definition, but applies for <code>string</code> types, i.e. <code>char</code> and <code>text</code>.
    The [validation rule] is defined as:</p>
    <source>[fieldName]%length = [1..10]</source>
    <p>Using <code>?</code> allows to keep one parameter unbound, which will default to a minimum length of 0 and a
    maxium length of 255</p>
    <p>To define that the CV needs to be at least 100 characters, define:</p>
    <source>cv%length = [100..?] : CV must be of decent length!</source>
    </section>

    <section id="regexp"><title>Regular expression rule</title>
    <p>The string regular expression rule applies for <code>string</code> types, primarily for <code>char</code>,
    but also for <code>text</code>. The [validation rule] is defined as:</p>
    <p>
    <code>[fieldName]%matches = regular expression</code></p>
    <p>Regular expressions must be valid regular expressions in Java, for more details please refer to the <a
      href="ext:javaregexp">specification</a> and <a
      href="ext:javaregexptutorial">tutorial</a>.</p>
    <p>To compare if a field contains a valid e-mail address, define:</p>
    <p>
    <code>email%matches = .+@.+\.[a-z]+ : Email address is not valid!</code></p>
    </section>

  
    <section id="comparison"><title>Comparison rule</title>
    <p>This rule allows to compare a field to a constant value or simple function calls.</p>
    <p>The following constants are currently available:</p>
    <table>
      <tr>
        <th>Constants</th>
        <th>Description</th>
        <th>Valid</th>
      </tr>
      <tr>
        <td>$now</td>
        <td>The current date and time.</td>
        <td rowspan="2"><code>date</code> types</td>
      </tr>
      <tr>
        <td>$today</td>
        <td>The current date, time set to 00:00.</td>
      </tr>
    </table>
    
    <p>The following functions are currently available:</p>
    <table>
      <tr>
        <th>Function</th>
        <th>Description</th>
        <th>Valid</th>
      </tr>
      <tr>
        <td>$date(.., .., .., .., .., ..)</td>
        <td>Constructs a date.<br />
        The function takes up to six arguments, for day, month, year, hours, minutes and seconds. If less than six
        arguments are passed, the missing values will be automatically set to the current date.<br />
        $now is available as a constant for the current date value, and + and - operators can be used to modify that
        value. e.g. <source>date($now,$now,$now - 5)</source> evaluates as the current date 5 years
        ago.</td>
        <td><code>date</code> types</td>
      </tr>
      <tr>
        <td>lower(..)</td>
        <td>Converts a string to lower case.</td>
        <td rowspan="2"><code>String</code>, i.e. 'char' and 'text' types</td>
      </tr>
      <tr>
        <td>upper(..)</td>
        <td>Converts a string to upper case.</td>
      </tr>
    </table>
    
    <p>Valid comparison operators are the ones defined in Java:</p>
    <table>
      <tr>
        <th>Operator</th>
        <th>Meaning</th>
      </tr>
      <tr>
        <td>==</td>
        <td>equal</td>
      </tr>
      <tr>
        <td>!=</td>
        <td>not equal</td>
      </tr>
      <tr>
        <td>&lt;</td>
        <td>less than</td>
      </tr>
      <tr>
        <td>&gt;</td>
        <td>less than</td>
      </tr>
      <tr>
        <td>=&lt;</td>
        <td>less than or equal</td>
      </tr>
      <tr>
        <td>&gt;=</td>
        <td>greater than or equal</td>
      </tr>
    </table>

    <p>To compare if someone is at least 15 years old, define the following validation rule:</p>
    <source>minimumAge%compare = birthdate >= date($now,$now,$now - 15) : You have to be at least 15 years old!</source>

    <p>To ensure that a field doesn't contain only lower-case values, define this rule:</p>
    <source>nameNotAllLower%compare = lower(name) != name : Your name must not contain only lower-case letters!</source>

    <p>Two fields can be compared in a similar way</p>
    <source>graduationCheck%compare = birthdate &lt; graduationDate : You cannot finish school before your birthdate!</source>
    
    </section>

    <section><title>Multi-field uniqueness definition</title>
    <p>Similar to the <a href="datadef.html#FieldAttributes"><em>unique</em> field attribute</a>, you can also define multi-field
    uniqueness contraints. These constraints can even span over several data definitions, if they are related via
    pointers.</p>

    <p>Multi-field uniqueness can be defined as follows</p>
    <source>uniqueAgeEmail%unique = age, email : the combination of age and email must be unique! </source>
    
    <note class="internals">If the fields are in the same data definition, the uniqueness definition will
    translate into a database level multi-field key and uniqueness will be enforced there.<br />
    Otherwise, Makumba will issue a query checking the uniqueness before new or edit operations.</note>

</section>
</section>
<section id="error"><title>Error message</title>
    <p>The error message that will be displayed if the validation fails.</p>
</section>  

  </body>
</document>