/// <summary>
/// Read implementation
/// </summary>
/// <param name="reader"></param>
/// <param name="context"></param>
/// <returns></returns>
private static DBQuery sReadXml(System.Xml.XmlReader reader, XmlReaderContext context)
{
DBQuery q = null;
DBClause c = null;
while (reader.EOF == false && reader.NodeType != System.Xml.XmlNodeType.Element)
{
if (!reader.Read())
{
break;
}
}
if (reader.NodeType == System.Xml.XmlNodeType.Element && XmlHelper.IsElementMatch(XmlHelper.Statement, reader, context))
{
while (reader.Read())
{
if (reader.NodeType == System.Xml.XmlNodeType.Element)
{
break;
}
}
if (!reader.EOF)
{
c = context.Factory.Read(reader.LocalName, reader, context);
if (c is DBQuery)
{
q = (DBQuery)c;
}
else
{
throw XmlHelper.CreateException("The Xml stream did not begin with a valid DBQuery node, and cannot be deserialized", reader, null);
}
}
else
{
throw XmlHelper.CreateException("The Xml stream did not begin with a valid DBQuery node, and cannot be deserialized", reader, null);
}
}
if (!reader.EOF)
{
while (reader.Read())
{
if (reader.NodeType == System.Xml.XmlNodeType.Element && reader.Name == XmlHelper.Parameters)
{
while (reader.Read())
{
if (reader.NodeType == System.Xml.XmlNodeType.Element && XmlHelper.IsElementMatch(XmlHelper.Parameter, reader, context))
{
string name = reader.GetAttribute(XmlHelper.Name);
DBParam param;
if (context.Parameters.TryGetParameter(name, out param))
{
param.ReadXml(reader, context);
}
}
}
}
}
}
return(q);
}
/// <summary>
/// Inputs the XmlReader and attempts to parse as a valid DbQuery with the
/// specified element namespace and prefix
/// </summary>
/// <param name="reader">The reader to load the DbQuery from</param>
/// <param name="ns">The namespace of the DBQuery elements</param>
/// <param name="prefix">The prefix</param>
/// <param name="factory">An XmlFactory that creates new DBClause instances from their known names</param>
/// <returns>The parsed DbQuery</returns>
public static DBQuery ReadXml(System.Xml.XmlReader reader, string ns, string prefix, XmlFactory factory)
{
XmlReaderContext context = new XmlReaderContext(ns, prefix, factory);
return(DBQuery.sReadXml(reader, context));
}
/// <summary>
/// Begins a new SELECT DISTINCT statement. Add fields and tables by using the methods on the instance returned
/// </summary>
/// <returns>A new DBSelectQuery to support statement chaining</returns>
public static DBSelectQuery SelectDistinct()
{
DBSelectQuery q = DBQuery.Select();
return(q.Distinct());
}
//
// readXml methods
//
#region public static DBQuery ReadXml(System.Xml.XmlReader reader)
/// <summary>
/// Inputs the XmlReader and attempts to parse as a valid DbQuery
/// </summary>
/// <param name="reader">The reader to load the DbQuery from</param>
/// <returns>The parsed DbQuery</returns>
public static DBQuery ReadXml(System.Xml.XmlReader reader)
{
return(DBQuery.ReadXml(reader, "http://schemas.perceiveit.co.uk/Query", ""));
}
/// <summary>
/// Begins a new SELECT statement with a limit of [count] items returned
/// </summary>
/// <param name="count">The total number of items to return</param>
/// <returns>A new DBSelectQuery to support statement chaining</returns>
public static DBSelectQuery SelectTopN(int count)
{
DBSelectQuery q = DBQuery.Select();
return(q.TopN(count));
}
