protected static DbLimitExpression MinimumLimit(DbExpression input, DbLimitExpression limit, DbExpression k)
{
// source.Limit(k).Limit(k2) -> source.Limit(Min(k, k2))
var newCount = CombineIntegers(limit.Limit, k, Math.Min);
return(input.Limit(newCount));
}
protected static DbLimitExpression SubtractFromLimit(DbExpression input, DbLimitExpression limit, DbExpression minusK)
{
var newCount = CombineIntegers(
limit.Limit, minusK,
(l, r) => r > l ? 0 : l - r); // can't limit to less than zero rows)
return(input.Limit(newCount));
}
private DbExpression RewriteLimitExpression(DbLimitExpression expression)
{
DbExpression dbExpression = this.Rewrite(expression.Argument);
if (!object.ReferenceEquals((object)expression.Argument, (object)dbExpression))
{
expression = dbExpression.Limit(expression.Limit);
}
return((DbExpression)expression);
}
private DbExpression RewriteLimitExpression(DbLimitExpression expression)
{
DbExpression rewrittenInput = Rewrite(expression.Argument);
if (!object.ReferenceEquals(expression.Argument, rewrittenInput))
{
// Note that here we use the original expression.Limit. It is safe to do so,
// because we only allow physical paging (i.e. Limit can only be a constant or parameter)
expression = rewrittenInput.Limit(expression.Limit);
}
return(expression);
}
protected static DbLimitExpression MinimumLimit(DbExpression input, DbLimitExpression limit, DbExpression k)
{
// source.Limit(k).Limit(k2) -> source.Limit(Min(k, k2))
var newCount = CombineIntegers(limit.Limit, k, Math.Min);
return input.Limit(newCount);
}
protected static DbLimitExpression SubtractFromLimit(DbExpression input, DbLimitExpression limit, DbExpression minusK)
{
var newCount = CombineIntegers(
limit.Limit, minusK,
(l, r) => r > l ? 0 : l - r); // can't limit to less than zero rows)
return input.Limit(newCount);
}