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<title>IndexedDBView <View></title>
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vlink="#551A8B" alink="#FF0000">
<p><font size="6" face="Bookman Old Style"><em><strong><u>dtl</u></strong></em></font></p>
<p><img src="stat.gif" width="6" height="6"> <!--end header--> <br>
</p>
<h1>IndexedDBView <View></h1>
<table border="0" cellpadding="0" cellspacing="0" width="100%">
<tr>
<td><img src="containers.gif" width="194" height="38"></td>
<td align="right"><img src="type.gif" width="194"
height="39"></td>
</tr>
<tr>
<td valign="top"><b>Category</b>: containers</td>
<td align="right" valign="top"><b>Component type</b>:
type</td>
</tr>
</table>
<h3>Description</h3>
<p>The <font size="2" face="Courier New">IndexedDBView </font>Container
is a refinement of a <a
href="http://www.sgi.com/tech/stl/UniqueAssociativeContainer.html">Unique
Associative Container</a> with the property that elements may be
bound to an underlying database and may be indexed by one or more
criteria.</p>
<h3>Definition</h3>
<p>Defined in the <font size="2" face="Courier New">IndexedDBView.h
</font><font size="3">header file.</font></p>
<h3>Refinement of</h3>
<p><a
href="http://www.sgi.com/tech/stl/UniqueAssociativeContainer.html">Unique
Associative Container</a> </p>
<h3>Associated types</h3>
<p>None, except for those defined by <a
href="http://www.sgi.com/tech/stl/UniqueAssociativeContainer.html">Unique
Associative Container</a>. </p>
<h3>Example</h3>
<p><pre><code><span class="codeComment">// "Example" class to hold rows from our database table</span>
class Example
{
public: <span class="codeComment">// tablename.columnname:</span>
int exampleInt; <span class="codeComment">// DB_EXAMPLE.INT_VALUE</span>
string exampleStr; <span class="codeComment">// DB_EXAMPLE.STRING_VALUE</span>
double exampleDouble; <span class="codeComment">// DB_EXAMPLE.DOUBLE_VALUE</span>
long exampleLong; <span class="codeComment">// DB_EXAMPLE.EXAMPLE_LONG</span>
TIMESTAMP_STRUCT exampleDate; <span class="codeComment">// DB_EXAMPLE.EXAMPLE_DATE</span>
Example(int exInt, const string &exStr, double exDouble, long exLong,
const TIMESTAMP_STRUCT &exDate) :
exampleInt(exInt), exampleStr(exStr), exampleDouble(exDouble), exampleLong(exLong),
exampleDate(exDate)
{ }
};
<span class="codeComment">// Parameter object to hold parameters for dynamic SQL query below </span>
class ParamObjExample
{
public:
int lowIntValue;
int highIntValue;
string strValue;
TIMESTAMP_STRUCT dateValue;
};
<span class="codeComment">// Create an association between table columns and fields in our object</span>
class BCAExampleObj
{
public:
void operator()(BoundIOs &boundIOs, Example &rowbuf)
{
boundIOs["INT_VALUE"] == rowbuf.exampleInt;
boundIOs["STRING_VALUE"] == rowbuf.exampleStr;
boundIOs["DOUBLE_VALUE"] == rowbuf.exampleDouble;
boundIOs["EXAMPLE_LONG"] == rowbuf.exampleLong;
boundIOs["EXAMPLE_DATE"] == rowbuf.exampleDate;
}
};
<span class="codeComment">// Create an association between query parameters and fields in our parameters object</span>
class BPAExampleObj
{
public:
void operator()(BoundIOs &boundIOs, ParamObjExample &paramObj)
{
boundIOs[0] == paramObj.lowIntValue;
boundIOs[1] == paramObj.highIntValue;
boundIOs[2] == paramObj.strValue;
boundIOs[3] == paramObj.dateValue;
}
};
<span class="codeComment">// Set parameters function for Example ... used by IndexedDBView<Example> to set dynamic query parameters
// Dynamic query parameters are indicated by (?) in our query string for the IndexedDBView</span>
void SetParamsExample(ParamObjExample &params)
{
<span class="codeComment">// set parameter values</span>
params.lowIntValue = 2;
params.highIntValue = 8;
params.strValue = "Example";
TIMESTAMP_STRUCT paramDate = {2000, 1, 1, 0, 0, 0, 0};
params.dateValue = paramDate;
}
<span class="codeComment">// Example of using an IndexDBView to read, insert and update records in a container / database</span>
void IndexedViewExample()
{
typedef DBView<Example, ParamObjExample> DBV;
DBV view("DB_EXAMPLE", BCAExampleObj(),
"WHERE INT_VALUE BETWEEN (?) AND (?) OR "
"STRING_VALUE = (?) OR EXAMPLE_DATE <= (?) ORDER BY EXAMPLE_LONG",
BPAExampleObj());
IndexedDBView<DBV> indexed_view(view, "UNIQUE PrimaryIndex; STRING_VALUE; AlternateIndex; EXAMPLE_LONG, EXAMPLE_DATE",
BOUND, USE_ALL_FIELDS, cb_ptr_fun(SetParamsExample));
<span class="codeComment">// Find the item where the STRING_VALUE matches the string "Foozle"</span>
IndexedDBView<DBV>::indexed_iterator idxview_it = indexed_view.find(string("Foozle"));
<span class="codeComment">// Update the item with the key of "Foozle", to read "Fizzle" instead</span>
if (idxview_it != indexed_view.end()) {
Example replacement;
replacement = *idxview_it;
replacement.exampleStr = "Fizzle";
indexed_view.replace(idxview_it, replacement);
}
<span class="codeComment">// Now find a second set of items using AlternateIndex
// The STL convention for equal_range is to return a pair consisting of:
// 1. an iterator referring to the beginning of the list of found items
// 2. an iterator pointing to the end of the list of found items.
// We will remove all items in this range.</span>
const TIMESTAMP_STRUCT date_criteria = {2000, 1, 1, 0, 0, 0, 0};
long long_criteria = 33;
IndexedDBView<DBV>::indexed_pair pr = indexed_view.equal_range_AK ("AlternateIndex", long_criteria, date_criteria);
idxview_it = pr.first;
cout << "*** Size before erase calls: " << indexed_view.size() << " ***"
<< endl;
<span class="codeComment">// Remove all items that match the criteria in our equal_range_AK lookup</span>
while (idxview_it != pr.second)
{
<span class="codeComment">// As iterator is invalidated upon an erase(), use a
// temporary iterator to point to DataObj to erase.
// Increment idxview_it before we erase so it will still be valid
// when we erase the DataObj.</span>
IndexedDBView<DBV>::indexed_iterator deleteMe = idxview_it;
idxview_it++;
indexed_view.erase(deleteMe);
}
cout << "*** Size after erase calls: " << indexed_view.size() << " ***"
<< endl;
<span class="codeComment">// Finally, insert a new item into the container</span>
pair<IndexedDBView<DBV>::iterator, bool> ins_pr;
ins_pr = indexed_view.insert(Example(459, "Unique String #1", 3.4, 1, date_criteria));
cout << "insertion succeded = " << (ins_pr.second == true ? "true": "false") << endl;
}
</code></pre> </p>
<h3>Public Base Classes</h3>
<p>None.</p>
<h3>Template parameters</h3>
<table border="1">
<tr>
<th>Parameter </th>
<th>Description </th>
<th>Default </th>
</tr>
<tr>
<td valign="top"><tt>View</tt> </td>
<td valign="top">The type of the SQL view (usually a <a
href="DBView.htm"><font size="2" face="Courier New">DBView</font></a><font
size="2" face="Courier New"> </font>instantiation which
will be used as the underlying view for the<font size="2"
face="Courier New"> IndexedDBView</font>).</td>
<td valign="top"> </td>
</tr>
</table>
<p> </p>
<h3>Notation</h3>
<table border="0">
<tr>
<td valign="top"><tt>X</tt> </td>
<td valign="top">A type that is a model of <font size="2"
face="Courier New">IndexedDBView </font></td>
</tr>
<tr>
<td valign="top"><tt>a</tt> </td>
<td valign="top">Object of type <tt>X</tt> </td>
</tr>
<tr>
<td valign="top"><tt>t</tt> </td>
<td valign="top">Object of type <tt>X::value_type</tt> </td>
</tr>
<tr>
<td valign="top"><tt>k</tt> </td>
<td valign="top">Object of type <tt>X::key_type</tt> </td>
</tr>
<tr>
<td valign="top"><tt>p</tt>, <tt>q</tt> </td>
<td valign="top">Object of type <tt>X::iterator</tt> </td>
</tr>
<tr>
<td valign="top"><tt>f1, f2, ..., fn</tt></td>
<td valign="top">A primitive C type such as <font
size="2" face="Courier New">int, double, float,</font>...
or STL <font size="2" face="Courier New">string</font></td>
</tr>
<tr>
<td valign="top"><tt>s</tt></td>
<td valign="top">A STL <font size="2" face="Courier New">string</font></td>
</tr>
</table>
<h3>Valid expressions</h3>
<p>In addition to the expressions defined in <a
href="http://www.sgi.com/tech/stl/UniqueAssociativeContainer.html">Unique
Associative Container</a>, the following expressions must be
valid. </p>
<table border="1">
<tr>
<th>Name </th>
<th>Expression </th>
<th>Type requirements </th>
<th>Return type </th>
</tr>
<tr>
<td valign="top">Default constructor </td>
<td valign="top"><pre>X a(
DBView<...> &view,
const string &IndexNamesAndFields,
BoundMode bm = UNBOUND,
KeyMode km = USE_ALL_FIELDS,
SetParamsFn IndexedDBViewParam = DefaultSetParams<ParamObj>())
</pre>
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</tr>
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<td valign="top">Find alternate key</td>
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