AppletTalk.com Java discussions newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Locks and transactions          AppletTalk.com Forum Index -> Java and Databases View previous topic :: View next topic   Author Message Maciej Guest Posted: Wed Oct 18, 2006 7:21 pm    Post subject: Locks and transactions Hi, I have some newbie's questions. I use some applications where there are two techniques handling with concurrent access do DB: - Multi-Read-Single-Write Lock - transactions based on JDBC After comparision of these solutions I have a few questions: 1. If I put a WRITE lock on a single table, no other can read or write this table, isn't ? 2. When I put a READ lcok on a single table, no other can write to this table, but others can read it, isn't ? 3. If I start to transactions on the same table, one during another, what happends when the second one finishes before first what happens? 4. Is my understanding is correct, that locks are safer but could block access to the table during concurrent access, whether transaction no? Thank you in advance, Maciej Back to top joeNOSPAM@BEA.com Guest Posted: Wed Oct 18, 2006 7:33 pm    Post subject: Re: Locks and transactions On Oct 18, 7:21 am, "Maciej" <mgawine...@gmail.com> wrote: Quote: Hi, I have some newbie's questions. I use some applications where there are two techniques handling with concurrent access do DB: - Multi-Read-Single-Write Lock - transactions based on JDBC After comparision of these solutions I have a few questions: 1. If I put a WRITE lock on a single table, no other can read or write this table, isn't ? 2. When I put a READ lcok on a single table, no other can write to this table, but others can read it, isn't ? 3. If I start to transactions on the same table, one during another, what happends when the second one finishes before first what happens? 4. Is my understanding is correct, that locks are safer but could block access to the table during concurrent access, whether transaction no? Thank you in advance, Maciej Hi. In the real world you have to become very familiar with how a given brand of DBMS does it's locking. There are some significant differences that make generalities useless. For instance, it takes some non-standard SQL to get Oracle to block other transactions from reading data. If you want to do this right, you have to dig into the DBMS documentation about locking and transactional concurrency, and then your application will work with *that* DBMS. Converting to run with a second type of DBMS will *not* be trivial. Good luck, Joe Weinstein at BEA Systems Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         AppletTalk.com Forum Index -> Java and Databases All times are GMT Page 1 of 1   Jump to: Select a forum Java Newsgroups----------------Java DiscussionsWeb-based java games comp.lang.java 3D Graphics API's for Java Java: Support and criticism Java System Announcements comp.lang.java.api JavaBeans Java and CORBA Java and Databases comp.lang.java.developer Java GUI Toolkits Java Help comp.lang.java.javascript JVM, native methods and hardware comp.lang.java.misc Java Language Programming Security and Java comp.lang.java.setup Java Software Tools comp.lang.java.tech ibm.software.java.linux  Non-English Java Newsgroups----------------Java Language (German)Language Java (Français)Java (Italian)  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.