/// <summary>
/// Build database SQL query clause for one criterion.
/// Assumes field is date.
/// </summary>
/// <param name="prefix">operator to precede clause, e.g. "AND"</param>
/// <param name="sf">StationField which describes the desired field</param>
/// <param name="c"></param>
/// <returns>empty string if c is null</returns>
public static string AddSqlDateClause(string prefix, StationField sf, Criterion c)
{
string clause = "";
if (c != null)
{
clause = " " + prefix + " ";
if (c.IsUnaryOperator())
{
clause += SqlUnaryOperation(c, sf);
}
else
{ // binary operator
// TODO Idea: recognize keyword like "TODAY", would require a special clause
// TODO "equals" for date doesn't work -- need to compare only the date,
// not the time (or adjust the end time to 11:59:59)
clause += sf.Location + " ";
clause += SqlBinaryOperator(c.Operation) +
" TO_DATE('" + c.Value + "','" + SqlDateFormat(c.Value) + "') ";
}
}
return clause;
}
/// <summary>
/// Build database SQL query clause for one criterion.
/// Assumes field is numeric.
/// </summary>
/// <param name="prefix">operator to precede clause, e.g. "AND"</param>
/// <param name="sf">StationField which describes the desired field</param>
/// <param name="c"></param>
/// <returns>empty string if c is null</returns>
public static string AddSqlNumberClause(string prefix, StationField sf, Criterion c)
{
string clause = "";
if (c != null)
{
clause = " " + prefix + " ";
if (c.IsUnaryOperator())
{
clause += SqlUnaryOperation(c, sf);
}
else
{ // binary operator
clause += sf.Location + " ";
clause += SqlBinaryOperator(c.Operation) +
// still use quotes in case it's not really a number field
// or the operator is "LIKE"
" '" + c.Value + "' ";
}
}
return clause;
}
/// <summary>
/// Build database SQL query clause for one criterion.
/// Assumes field is string or string-compatible.
/// </summary>
/// <param name="prefix">operator to precede clause, e.g. "AND"</param>
/// <param name="sf">StationField which describes the desired field</param>
/// <param name="c"></param>
/// <returns>empty string if c is null</returns>
public static string AddSqlTextClause(string prefix, StationField sf, Criterion c)
{
string clause = "";
if (c != null)
{
clause = " " + prefix + " ";
if (c.IsUnaryOperator())
{
clause += SqlUnaryTextOperation(c, sf);
}
else
{ // binary operator
clause += sf.Location + " ";
clause += SqlBinaryOperator(c.Operation) +
" '" + c.Value + "' ";
}
}
return clause;
}