database-concurrency

A while ago, I wrote an application used by multiple users to handle trades creation. I haven't done development for some time now, and I can't remember how I managed the concurrency between the users. Thus, I'm seeking some advice in terms of design. The original application had the following characteristics: One heavy client per user. A single database. Access to the database for each user to insert/update/delete trades. A grid in the application reflecting the trades table. That grid being updated each time someone changes a deal. I am using WPF. Here's what I'm wondering: Am I correct in

Consider the scenario: A Db transaction envolving more than one row from different tables with versioning. For example: A shopLists and products. Where a shopList may contain products (with their amount in the shoplist) and products have their current stock. When I insert ou edit a shopList, I want the stock of those products in the shopList to be updated to keep the stock consistant. To do that, I open a transaction, insert/update the shopList, update the stocks for each product (apply delta) and then commit the transaction. No big deal up to now. However, other user may have updated one or

According to the reference documentation the READ ONLY transaction flag is useful other than allowing DEFERRABLE transactions? SET SESSION CHARACTERISTICS AS TRANSACTION READ ONLY; The DEFERRABLE transaction property has no effect unless the transaction is also SERIALIZABLE and READ ONLY. When all three of these properties are selected for a transaction, the transaction may block when first acquiring its snapshot, after which it is able to run without the normal overhead of a SERIALIZABLE transaction and without any risk of contributing to or being canceled by a serialization failure. This