internal virtual SqlExpression VisitSimpleCase(SqlSimpleCase c)
{
c.Expression = this.VisitExpression(c.Expression);
for (int i = 0, n = c.Whens.Count; i < n; i++)
{
SqlWhen when = c.Whens[i];
when.Match = this.VisitExpression(when.Match);
when.Value = this.VisitExpression(when.Value);
}
return(c);
}
internal virtual SqlExpression VisitSearchedCase(SqlSearchedCase c)
{
for (int i = 0, n = c.Whens.Count; i < n; i++)
{
SqlWhen when = c.Whens[i];
when.Match = this.VisitExpression(when.Match);
when.Value = this.VisitExpression(when.Value);
}
c.Else = this.VisitExpression(c.Else);
return(c);
}
internal override SqlExpression VisitSimpleCase(SqlSimpleCase c)
{
SqlExpression expr = this.VisitExpression(c.Expression);
SqlWhen[] whens = new SqlWhen[c.Whens.Count];
for (int i = 0, n = whens.Length; i < n; i++)
{
SqlWhen when = c.Whens[i];
whens[i] = new SqlWhen(this.VisitExpression(when.Match), this.VisitExpression(when.Value));
}
return(new SqlSimpleCase(c.ClrType, expr, whens, c.SourceExpression));
}
internal override SqlExpression VisitSimpleCase(SqlSimpleCase c)
{
SqlExpression expr = VisitExpression(c.Expression);
var array = new SqlWhen[c.Whens.Count];
var i = 0;
for (var num = array.Length; i < num; i++)
{
var sqlWhen = c.Whens[i];
array[i] = new SqlWhen(VisitExpression(sqlWhen.Match), VisitExpression(sqlWhen.Value));
}
return(new SqlSimpleCase(c.ClrType, expr, array, c.SourceExpression));
}
internal override SqlExpression VisitSimpleCase(SqlSimpleCase c)
{
c.Expression = this.VisitExpression(c.Expression);
int compareWhen = 0;
// Find the ELSE if it exists.
for (int i = 0, n = c.Whens.Count; i < n; i++)
{
if (c.Whens[i].Match == null)
{
compareWhen = i;
break;
}
}
c.Whens[compareWhen].Match = VisitExpression(c.Whens[compareWhen].Match);
c.Whens[compareWhen].Value = VisitExpression(c.Whens[compareWhen].Value);
// Compare each other when value to the compare when
List <SqlWhen> newWhens = new List <SqlWhen>();
bool allValuesLiteral = true;
for (int i = 0, n = c.Whens.Count; i < n; i++)
{
if (compareWhen != i)
{
SqlWhen when = c.Whens[i];
when.Match = this.VisitExpression(when.Match);
when.Value = this.VisitExpression(when.Value);
if (!SqlComparer.AreEqual(c.Whens[compareWhen].Value, when.Value))
{
newWhens.Add(when);
}
allValuesLiteral = allValuesLiteral && when.Value.NodeType == SqlNodeType.Value;
}
}
newWhens.Add(c.Whens[compareWhen]);
// Did everything reduce to a single CASE?
SqlExpression rewrite = TryToConsolidateAllValueExpressions(newWhens.Count, c.Whens[compareWhen].Value);
if (rewrite != null)
{
return(rewrite);
}
// Can it be a conjuction (or disjunction) of clauses?
rewrite = TryToWriteAsSimpleBooleanExpression(c.ClrType, c.Expression, newWhens, allValuesLiteral);
if (rewrite != null)
{
return(rewrite);
}
// Can any WHEN clauses be reduced to fall into the ELSE clause?
rewrite = TryToWriteAsReducedCase(c.ClrType, c.Expression, newWhens, c.Whens[compareWhen].Match, c.Whens.Count);
if (rewrite != null)
{
return(rewrite);
}
return(c);
}
