// ---------- Convenience statics ----------
///<summary>
/// Returns a FunctionTable that has a single Expression evaluated in it.
///</summary>
///<param name="context"></param>
///<param name="expression"></param>
/// <remarks>
/// The column name is 'result'.
/// </remarks>
///<returns></returns>
public static Table ResultTable(IQueryContext context, Expression expression)
{
Expression[] exp = new Expression[] { expression };
string[] names = new String[] { "result" };
Table function_table = new FunctionTable(exp, names, context);
SubsetColumnTable result = new SubsetColumnTable(function_table);
int[] map = new int[] { 0 };
ObjectName[] vars = new[] { new ObjectName("result") };
result.SetColumnMap(map, vars);
return(result);
}
public override ITable Evaluate(IQueryContext context)
{
Table t = (Table) Child.Evaluate(context);
int sz = originalColumns.Length;
int[] colMap = new int[sz];
for (int i = 0; i < sz; ++i) {
int mapped = t.FindFieldName(originalColumns[i]);
if (mapped == -1)
throw new InvalidOperationException(String.Format("Column {0} was not found in table {1} when subsetting.", originalColumns[i], t.TableInfo.Name));
colMap[i] = mapped;
}
var subsetTable = new SubsetColumnTable((Table)t);
subsetTable.SetColumnMap(colMap, newColumnNames);
return subsetTable;
}
// ---------- Convenience statics ----------
///<summary>
/// Returns a FunctionTable that has a single Expression evaluated in it.
///</summary>
///<param name="context"></param>
///<param name="expression"></param>
/// <remarks>
/// The column name is 'result'.
/// </remarks>
///<returns></returns>
public static Table ResultTable(IQueryContext context, Expression expression)
{
Expression[] exp = new Expression[] { expression };
string[] names = new String[] {"result"};
Table function_table = new FunctionTable(exp, names, context);
SubsetColumnTable result = new SubsetColumnTable(function_table);
int[] map = new int[] {0};
ObjectName[] vars = new[] {new ObjectName("result")};
result.SetColumnMap(map, vars);
return result;
}