c# - implementing a locking/checking mechanism for stock quantity when users concurrently buy the same thing -

-

im new please forgive mistakes. im building ecommerce platform sell goods. want ensure if multiple users buy same product @ around same time. user should not allowed go payment if enough stock not available. problem im not decreasing stock database until payment made.while 1 user makes payment others stock might still appear full , in turn place orders stock doesnt exist. need direction implement kind of locking mechanism product stock under processing. how while booking movie tickets seat blocked until transaction completes else released.i want implement same stock. ideas? im using asp.net c#

well, reason why can't come solution because don't have implementation, rather business problem.

once business policies defined, implementation easy.

for example, amazon allows ordering or products running out saying "we'll deliver in 2-4 weeks". meaning, can still order, you'll product later / emailed once it's on way.

in case, however, if have finite resources (seats / movie tickets) - can start putting people in waiting list. like, warn them running out of seats, allow them complete process normally. processing payments, can send more detailed emails left without seat. kinda airlines do. once sort out bought tickets refund left without seats.

if problem deeper (like thinking blocking individual seats) - think more business policies. like, need go down level? can't airlines doing (sell tickets class first, , later allow users pick seats)? again - core of problem business, rather implementation. once use cases defined, you'll need use standard database locks.

the important thing in processes transparency. honest users. keep them informed through process , don't try trick them - show more seats there is, incentify them complete purchase.


Comments

Post a Comment

Popular posts from this blog

PHP DOM loadHTML() method unusual warning -

-
i had following code works fine on localhost: $document = new domdocument(); $document->loadhtml($p_result); $form = $document->getelementsbytagname('form')->item(0); // code continues using $form variable after same code updated on outside server, loadhtml() failed , issued warning. warning: domdocument::loadhtml() expects parameter 1 valid path, string given in path/name/to/script.php returned null instead of object code pretty gets fatal error. note contents of $p_result absolutely same on outside server , on localhost. but why displays kind of warning , why not work? doesn't loadhtml() expects argument 1 string in first place? why method expects parameter 1 valid path ? just make clear i'm not calling loadhtmlfile() , i'm calling loadhtml() . thanks. you're affected one of php bugs . issue present in php 5.6.8 , 5.6.9. have affected php version on server, , bug-free version on localhost. the bug forbids null
Read more

python - How to create jsonb index using GIN on SQLAlchemy? -

-
here's current code creating index jsonb. index("mytable_data_idx_id_key", mytable.data['id'].astext, postgresql_using='gin') but got error. sqlalchemy.exc.programmingerror: (psycopg2.programmingerror) data type text has no default operator class access method "gin" hint: must specify operator class index or define default operator class data type. [sql: "create index event_data_idx_id_key on event using gin ((data ->> 'id'))"] is there way create index on sqlalchemy? the postgresql specific sqlalchemy docs @ http://docs.sqlalchemy.org/en/latest/dialects/postgresql.html#operator-classes mention postgresql_ops dictionary provide "operator class" used postgresql, , provide example illustrating use: index('my_index', my_table.c.id, my_table.c.data, postgresql_ops={ 'data': 'text_pattern_ops',
Read more

c# - TransactionScope not rolling back although no complete() is called -

-
i'm using transactionscope rollback transaction fail bool errorreported = false; action<importerrorlog> newerrorcallback = e => { errorreported = true; errorcallback(e); }; using (var transaction = new transactionscope()) { foreach (importtaskdefinition task in taskdefinition) { loader.load(streamfile, newerrorcallback, task.destinationtable, processingtaskid); } if (!errorreported) transaction.complete(); } i'm sure there no transactionscope started ahead or after code. i'm using entity framework insert in db. regardless state of errorreported transaction never rolled in case of error. what missing ? transactionscope sets transaction.current . that's does. wants transacted must @ property. i believe ef each time connection opened reason. probably, connection open when scope installed. open connection inside of scope or enlist manually. ef has nasty "design decision": default opens
Read more