public void Compile(ObjectExpression oe)
{
_maps = oe.Mappings;
_provider = oe.Mappings.provider;
_nextAliasIndex = 0;
_parameterTable = new OPathParameterTable();
// generate the database-specific query statement (and the parameter table at the same time)
using( StringWriter writer = new StringWriter(new StringBuilder(500)) )
{
WriteSqlQuery(writer, oe.Expression);
writer.Write(_provider.LineTerminator);
_sqlQuery = writer.ToString();
}
SetParameterOrder(oe);
// all or none of the parameters have to be provided
if( _parameterTable != null )
{
if( _parameterTable.Count != oe.ParameterCount )
{
throw new Exception("Number of parameters in the expression does not match number of parameters in the OPathQuery.");
}
}
#if DEBUG
//Debug.WriteLine(_sqlQuery);
//Debug.WriteLine("");
#endif
}
internal static ObjectExpression Parse(OPathQuery query, Mappings maps)
{
OPath opath = new OPath(maps);
int paramCount;
Expression exp = opath.Parse(query.ObjectType, query.WhereExpression, query.SortExpression, out paramCount);
ObjectExpression oe = new ObjectExpression(query.ObjectType, exp, maps, paramCount);
oe.baseQuery = query;
return oe;
}
internal CompiledQuery(ObjectExpression oe)
{
_objectExpression = oe;
_objectType = oe.ObjectType;
this.baseQuery = oe.baseQuery;
this.parameterCount = oe.ParameterCount;
OPathCompiler compiler = new OPathCompiler();
compiler.Compile(oe);
_sqlQuery = compiler.SqlQuery;
this.parameterTable = compiler.ParameterTable;
}
private void SetParameterOrder(ObjectExpression oe)
{
if( oe.ParameterCount == 0 ) return;
if( _provider.Provider == Provider.Access || _provider.Provider == Provider.OleDb )
{
// the OleDb driver expects the order of parameters to be specified in "subquery major" order (which I consider a *major* design flaw).
// in other words, the order is driven by a post traversal of the select statements (filters), with standard left-to-right order within a given select.
Expression.EnumNodesCallBack postCallback = new Expression.EnumNodesCallBack(this.OleDbSetParameterOrder);
Expression.EnumNodes(oe.Expression, null, postCallback, 0);
}
else // not an OleDb provider
{
// use standard right-to-left order (which the parameters are already in)
for( int i = _parameterTable.Count - 1; i >= 0; i-- )
{
_parameterTable[i].Ordinal = i;
}
}
}