private static ISqlFragment WriteInstanceFunctionCall(
SqlGenerator sqlgen, string functionName, DbFunctionExpression functionExpression, bool isPropertyAccess,
string castReturnTypeTo)
{
Debug.Assert(
!isPropertyAccess || functionExpression.Arguments.Count == 1,
"Property accessor instance functions should have only the single instance argument");
return WrapWithCast(
castReturnTypeTo, result =>
{
var instanceExpression = functionExpression.Arguments[0];
// Write the instance - if this is another function call, it need not be enclosed in parentheses.
if (instanceExpression.ExpressionKind
!= DbExpressionKind.Function)
{
sqlgen.ParenthesizeExpressionIfNeeded(instanceExpression, result);
}
else
{
result.Append(instanceExpression.Accept(sqlgen));
}
result.Append(".");
result.Append(functionName);
if (!isPropertyAccess)
{
WriteFunctionArguments(sqlgen, functionExpression.Arguments.Skip(1), result);
}
});
}
/// <summary>
/// Helper for all date and time types creating functions.
///
/// The given expression is in general trainslated into:
///
/// CONVERT(@typename, [datePart] + [timePart] + [timeZonePart], 121), where the datePart and the timeZonePart are optional
///
/// Only on Katmai, if a date part is present it is wrapped with a call for adding years as shown below.
/// The individual parts are translated as:
///
/// Date part:
/// PRE KATMAI: convert(varchar(255), @year) + '-' + convert(varchar(255), @month) + '-' + convert(varchar(255), @day)
/// KATMAI: DateAdd(year, @year-1, covert(@typename, '0001' + '-' + convert(varchar(255), @month) + '-' + convert(varchar(255), @day) + [possibly time ], 121)
///
/// Time part:
/// PRE KATMAI: convert(varchar(255), @hour)+ ':' + convert(varchar(255), @minute)+ ':' + str(@second, 6, 3)
/// KATMAI: convert(varchar(255), @hour)+ ':' + convert(varchar(255), @minute)+ ':' + str(@second, 10, 7)
///
/// Time zone part:
/// (case when @tzoffset >= 0 then '+' else '-' end) + convert(varchar(255), ABS(@tzoffset)/60) + ':' + convert(varchar(255), ABS(@tzoffset)%60)
///
/// </summary>
/// <param name="typeName"></param>
/// <param name="args"></param>
/// <param name="hasDatePart"></param>
/// <param name="hasTimeZonePart"></param>
/// <returns></returns>
private static ISqlFragment HandleCanonicalFunctionDateTimeTypeCreation(
SqlGenerator sqlgen, string typeName, IList<DbExpression> args, bool hasDatePart, bool hasTimeZonePart)
{
Debug.Assert(
args.Count == (hasDatePart ? 3 : 0) + 3 + (hasTimeZonePart ? 1 : 0),
"Invalid number of parameters for a date time creating function");
var result = new SqlBuilder();
var currentArgumentIndex = 0;
if (!sqlgen.IsPreKatmai && hasDatePart)
{
result.Append("DATEADD(year, ");
sqlgen.ParenthesizeExpressionIfNeeded(args[currentArgumentIndex++], result);
result.Append(" - 1, ");
}
result.Append("convert (");
result.Append(typeName);
result.Append(",");
//Building the string representation
if (hasDatePart)
{
// YEAR: PREKATMAI: CONVERT(VARCHAR, @YEAR)
// KATMAI : '0001'
if (!sqlgen.IsPreKatmai)
{
result.Append("'0001'");
}
else
{
AppendConvertToVarchar(sqlgen, result, args[currentArgumentIndex++]);
}
// MONTH
result.Append(" + '-' + ");
AppendConvertToVarchar(sqlgen, result, args[currentArgumentIndex++]);
// DAY
result.Append(" + '-' + ");
AppendConvertToVarchar(sqlgen, result, args[currentArgumentIndex++]);
result.Append(" + ' ' + ");
}
// HOUR
AppendConvertToVarchar(sqlgen, result, args[currentArgumentIndex++]);
// MINUTE
result.Append(" + ':' + ");
AppendConvertToVarchar(sqlgen, result, args[currentArgumentIndex++]);
// SECOND
result.Append(" + ':' + str(");
result.Append(args[currentArgumentIndex++].Accept(sqlgen));
if (sqlgen.IsPreKatmai)
{
result.Append(", 6, 3)");
}
else
{
result.Append(", 10, 7)");
}
// TZOFFSET
if (hasTimeZonePart)
{
result.Append(" + (CASE WHEN ");
sqlgen.ParenthesizeExpressionIfNeeded(args[currentArgumentIndex], result);
result.Append(" >= 0 THEN '+' ELSE '-' END) + convert(varchar(255), ABS(");
sqlgen.ParenthesizeExpressionIfNeeded(args[currentArgumentIndex], result);
result.Append("/60)) + ':' + convert(varchar(255), ABS(");
sqlgen.ParenthesizeExpressionIfNeeded(args[currentArgumentIndex], result);
result.Append("%60))");
}
result.Append(", 121)");
if (!sqlgen.IsPreKatmai && hasDatePart)
{
result.Append(")");
}
return result;
}