ibm-information-center/dist/eclipse/plugins/i5OS.ic.db2_5.4.0.1/rbafzmstsignal.htm

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<a name="signal"></a>
<h2 id="signal"><a href="rbafzmst02.htm#ToC_1369">SIGNAL</a></h2><a id="idx3239" name="idx3239"></a><a id="idx3240" name="idx3240"></a>
<p>The SIGNAL statement signals an error or warning condition. It causes an
error or warning to be returned with the specified SQLSTATE and optional <span class="italic">condition-information-items</span>.</p>
<a name="wq1818"></a>
<h3 id="wq1818"><a href="rbafzmst02.htm#ToC_1370">Invocation</a></h3>
<p>This statement can only be embedded in an application program. It is an
executable statement that cannot be dynamically prepared. It must not be specified
in REXX.</p>
<a name="wq1819"></a>
<h3 id="wq1819"><a href="rbafzmst02.htm#ToC_1371">Authorization</a></h3>
<p>None required.</p>
<a name="wq1820"></a>
<h3 id="wq1820"><a href="rbafzmst02.htm#ToC_1372">Syntax</a></h3>
<a href="rbafzmstsignal.htm#synsignal"><img src="c.gif" alt="Click to skip syntax diagram" /></a>
<p> </p>
<a name="wq1821"></a>
<div class="fignone" id="wq1821">
<pre class="cgraphic"><span><img src="c.gif" alt="Read syntax diagram" longdesc="rbafzmstsyn396.htm"
border="0" /></span><a href="#skipsyn-395"><img src="c.gif" alt="Skip visual syntax diagram"
border="0" /></a> .-VALUE-.
>>-SIGNAL-SQLSTATE--+-------+--+-<span class="italic">sqlstate-string-constant</span>-+----->
'-<span class="italic">sqlstate-string-variable</span>-'
>--+--------------------+-------------------------------------->&lt;
'-<span class="italic">signal-information</span>-'
signal-information:
.-,-----------------------------------------------------------.
V |
|--SET----+-MESSAGE_TEXT-------+--&nbsp;=&nbsp;--+-<span><span class="italic">variable</span></span>-------------------+-+--|
+-CONSTRAINT_CATALOG-+ '-<span class="italic">diagnostic-string-constant</span>-'
+-CONSTRAINT_SCHEMA--+
+-CONSTRAINT_NAME----+
+-CATALOG_NAME-------+
+-SCHEMA_NAME--------+
+-TABLE_NAME---------+
+-COLUMN_NAME--------+
+-CURSOR_NAME--------+
+-CLASS_ORIGIN-------+
'-SUBCLASS_ORIGIN----'
</pre>
<a name="skipsyn-395" id="skipsyn-395"></a></div>
<a name="synsignal"></a>
<h3 id="synsignal"><a href="rbafzmst02.htm#ToC_1373">Description</a></h3>
<dl class="parml">
<dt class="bold">SQLSTATE VALUE</dt>
<dd>Specifies the SQLSTATE that will be signalled. The specified
value must not be null and must follow the rules for SQLSTATEs:
<ul>
<li>Each character must be from the set of digits ('0' through '9') or non-accented
upper case letters ('A' through 'Z').</li>
<li>The SQLSTATE class (first two characters) cannot be '00' since this represents
successful completion.</li></ul>
<p>If the SQLSTATE does not conform to these rules, an error is returned.</p>
<dl class="parml">
<dt class="bold"><span class="italic">sqlstate-string-constant</span></dt>
<dd>The <span class="italic">sqlstate-string-constant</span> must be a character
string constant with exactly 5 characters.
</dd>
<dt class="bold"><span class="italic">sqlstate-string-variable</span></dt>
<dd>The <span class="italic">sqlstate-string-variable</span> must be a character,
UTF-16 graphic, or UCS-2 graphic variable. The actual length of the contents
of the <var class="pv">variable</var> must be 5.
</dd>
</dl>
</dd>
<dt class="bold">SET</dt>
<dd>Introduces the assignment of values to <span class="italic">condition-information-items</span>. The <span class="italic">condition-information-item</span> values can be
accessed using the GET DIAGNOSTICS statement. The only <span class="italic">condition-information-item</span> that can be accessed in the SQLCA is MESSAGE_TEXT.
<dl class="parml">
<dt class="bold">MESSAGE_TEXT</dt><a id="idx3241" name="idx3241"></a>
<dd>Specifies a string that describes the error or warning.
<p>If an SQLCA
is used, </p>
<ul>
<li>the string is returned in the SQLERRMC field of the SQLCA</li>
<li>if the actual length of the string is longer than 70 bytes, it is truncated
without a warning.</li></ul>
</dd>
<dt class="bold">CONSTRAINT_CATALOG</dt><a id="idx3242" name="idx3242"></a>
<dd>Specifies a string that indicates the name of the database that contains
a constraint related to the signalled error or warning.
</dd>
<dt class="bold">CONSTRAINT_SCHEMA</dt><a id="idx3243" name="idx3243"></a>
<dd>Specifies a string that indicates the name of the schema that contains
a constraint related to the signalled error or warning.
</dd>
<dt class="bold">CONSTRAINT_NAME</dt><a id="idx3244" name="idx3244"></a>
<dd>Specifies a string that indicates the name of a constraint related to
the signalled error or warning.
</dd>
<dt class="bold">CATALOG_NAME</dt><a id="idx3245" name="idx3245"></a>
<dd>Specifies a string that indicates the name of the database that contains
a table or view related to the signalled error or warning.
</dd>
<dt class="bold">SCHEMA_NAME</dt><a id="idx3246" name="idx3246"></a>
<dd>Specifies a string that indicates the name of the schema that contains
a table or view related to the signalled error or warning.
</dd>
<dt class="bold">TABLE_NAME</dt><a id="idx3247" name="idx3247"></a>
<dd>Specifies a string that indicates the name of a table or view related
to the signalled error or warning.
</dd>
<dt class="bold">COLUMN_NAME</dt><a id="idx3248" name="idx3248"></a>
<dd>Specifies a string that indicates the name of a column in the table
or view related to the signalled error or warning.
</dd>
<dt class="bold">CURSOR_NAME</dt><a id="idx3249" name="idx3249"></a>
<dd>Specifies a string that indicates the name of a cursor related to the
signalled error or warning.
</dd>
<dt class="bold">CLASS_ORIGIN</dt><a id="idx3250" name="idx3250"></a>
<dd>Specifies a string that indicates the origin of the SQLSTATE class related
to the signalled error or warning.
</dd>
<dt class="bold">SUBCLASS_ORIGIN</dt><a id="idx3251" name="idx3251"></a>
<dd>Specifies a string that indicates the origin of the SQLSTATE subclass
related to the signalled error or warning.
</dd>
<dt class="bold"><span class="italic">variable</span></dt>
<dd>Identifies a variable that must be declared in accordance with the rules
for declaring variables (see <a href="rbafzmstch2refvar.htm#ch2host">References to host variables</a>). The variable contains
the value to be assigned to the <span class="italic">condition-information-item</span>. The variable must be defined as CHAR, VARCHAR, UTF-16 or UCS-2 GRAPHIC,
or UTF-16 or UCS-2 VARGRAPHIC variable.
</dd>
<dt class="bold"><span class="italic">diagnostic-string-constant</span></dt>
<dd>Specifies a character string constant that contains the value to be
assigned to the <span class="italic">condition-information-item</span>.
</dd>
</dl>
</dd>
</dl>
<a name="wq1822"></a>
<h3 id="wq1822"><a href="rbafzmst02.htm#ToC_1374">Notes</a></h3>
<p><span class="bold">SQLSTATE values:</span> Any valid SQLSTATE value can be
used in the SIGNAL statement. However, it is recommended that programmers
define new SQLSTATEs based on ranges reserved for applications. This prevents
the unintentional use of an SQLSTATE value that might be defined by the database
manager in a future release.</p>
<p>SQLSTATE values are comprised of a two-character class code value, followed
by a three-character subclass code value. Class code values represent classes
of successful and unsuccessful execution conditions.</p>
<ul>
<li>SQLSTATE classes that begin with the characters '7' through '9' or 'I'
through 'Z' may be defined. Within these classes, any subclass may be defined.</li>
<li>SQLSTATE classes that begin with the characters '0' through '6' or 'A'
through 'H' are reserved for the database manager. Within these classes,
subclasses that begin with the characters '0' through 'H' are reserved for
the database manager. Subclasses that begin with the characters 'I' through
'Z' may be defined.</li></ul>
<p>For more information about SQLSTATEs, see the<a href="../rzala/rzalakickoff.htm"> SQL Messages
and Codes</a> book in the iSeries Information Center.</p>
<p><span class="bold">Assignment:</span> When the SIGNAL statement is executed,
the value of each of the specified <span class="italic">string-constants</span> and <span class="italic">variables</span> is assigned (using storage assignment
rules) to the corresponding <span class="italic">condition-information-item</span>. For details on the assignment rules, see <a href="rbafzmstch2bas.htm#ch2bas">Assignments and comparisons</a>. For
details on the maximum length of specific <span class="italic">condition-information-items</span>, see <a href="rbafzmstgetdiag.htm#getdiag">GET DIAGNOSTICS</a>.</p>
<p><span class="bold">Processing a SIGNAL statement:</span> When a SIGNAL statement
is issued, the SQLCODE is based on the SQLSTATE value as follows:</p>
<ul>
<li>If the specified SQLSTATE class is either '01' or '02', a warning or not
found is signalled and the SQLCODE is set to +438.</li>
<li>Otherwise, an exception is signalled and the SQLCODE is set to &ndash;438.</li></ul>
<a name="wq1823"></a>
<h3 id="wq1823"><a href="rbafzmst02.htm#ToC_1375">Examples</a></h3>
<p><span class="italic">Example 1:</span> Signal SQLSTATE '75002' with a descriptive
message text. </p>
<pre class="xmp"> EXEC SQL <span class="bold">SIGNAL SQLSTATE</span> '75002'
<span class="bold">SET MESSAGE_TEXT =</span> 'Customer number is not known';</pre>
<p><span class="italic">Example 2:</span> Signal SQLSTATE '75002' with a descriptive
message text and associate a specific table with the error. </p>
<pre class="xmp"> EXEC SQL <span class="bold">SIGNAL SQLSTATE</span> '75002'
<span class="bold">SET MESSAGE_TEXT =</span> 'Customer number is not known',
<span class="bold"> SCHEMA_NAME =</span> 'CORPDATA',
<span class="bold"> TABLE_NAME =</span> 'CUSTOMER';</pre>
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