public bool LoanBook(int ssn, int copyId)
{
using (var dbContextTransaction = _context.Database.BeginTransaction(IsolationLevel.Serializable))
{
try
{
if (_loaningDa.MemberLoanBooks(ssn, _context) < _memberDa.GetMember(ssn, _context).MemberType.NrOfBooks && //member is allowed to Loan more
_loaningDa.GetLoan(copyId, _context) == null && //not Loaned at the time
_loaningDa.LoanBook(new Loan {
SSN = ssn, CopyID = copyId, FromDate = DateTime.Now
}, _context)) //loan successful
{
dbContextTransaction.Commit();
return(true);
}
dbContextTransaction.Rollback();
return(false);
}
catch
{
dbContextTransaction.Rollback();
return(false);
}
}
}
public int GetAvailableCopyId(string isbn)
{
using (var dbContextTransaction = _context.Database.BeginTransaction(IsolationLevel.ReadUncommitted))
{
try
{
var copies = _copyDa.GetAvailableCopyId(isbn, _context);
int i = 0;
if (copies.Count > 0)
{
while (!false)
{
if (_loaningDa.GetLoan(copies[i].CopyID, _context) == null)
{
dbContextTransaction.Commit();
return(copies[i].CopyID);
}
else
{
i++;
}
}
}
dbContextTransaction.Rollback();
return(0);
}
catch
{
dbContextTransaction.Rollback();
return(0);
}
}
}
//todo wrong location
private List <readAllMaterial> CountAvailableCopies(List <readAllMaterial> allMaterials, List <Copy> copies)
{
foreach (var readAllMaterial in allMaterials)
{
int count = 0;
foreach (var copy in copies)
{
if (readAllMaterial.ISBN.Equals(copy.ISBN) && readAllMaterial.Location.Equals(copy.LibraryName) &&
readAllMaterial.TypeName.Equals(copy.TypeName) &&
(_loaningDa.GetLoan(copy.CopyID, _context) == null))
{
count++;
}
}
readAllMaterial.Available_Copies = count;
}
allMaterials = allMaterials.OrderByDescending(x => x.Available_Copies).ToList();
return(allMaterials);
}
