Update: Nov 24, 2003 ------------------------------------------------------------------------ 1. For Question I (2), assume the order of the B+ tree to be 1, i.e. nodes and pages have a minimum occupancy of 1 and a maximum occupancy of 2. 2. In Question II (2), take "serializable" for "conflict serializable" 3. The simplest way to check for serializability is to first construct the serializability graph and then check for acyclicity in that graph ! 4. IMPORTANT: for Question I, do either 1+2+3 or 2+3+4 !!!!!!!!!!!!!! --------------- 1. Pour la question I (2), supposez que l'ordre de l'arbre B+ est de 1, i.e. il a un minimum d'occupation de 1 et un maximum de 2. 2. Dans la Question II (2), "serialisable" est a prendre au sens de "serialisable par rapport aux conflits". 3. La meilleure facon de verifier la serialisabilite est d'abord de construire le graphe de serialisabilite et d'ensuite verifier si ce graphe ne contient pas des cycles. Update as of Oct 30, 2003 ------------------------------------------------------------------------- For tomorrow's submission, do not spend too much time on having a perfect Oracle script. We need just to see the translation from the ER-diagram to SQL statements. ----------------- Also, since Oracle is so restrictive about checks, please only do indicate how you would implement it. I suggest 2 ways: simple triggers, or at the application logic level when you will do the second part of the project. In any case indicate in the submission you hand in tomorrow which way you'll follow. A cause des restrictions de Oracle a propos des checks, je suggere 2 solutions: soit utiliser des triggers, soit resoudre ce probleme au niveau de la logique de l'application dans la 2eme phase du projet. Priere d'indiquer dans la soummission de demain comment vous aller resoudre ce probleme dans la suite du projet. FAQ-list as of this October 27 2003 ------------------------------------------------------------------ > I am the teaching assistant of CSI3317B (database). Now the students have > a project need to use JDBC. Could you please give me the information about > our server name and port numbers? > > Example: we need to use java code > > Connection conn = DriverManager.getConnection (url, "user", "passwd"); > > to create a connection object. But here url is a variable. I think if you > can offer me the information about site's url then I can create a connection > object in java. > > Example value of ulr: > url = "jdbc:oracle:thin:@oracle-prod:1521:OPROD" > > > Thank you very much! Hi Minjie, Since this is a good question, I will cc the answer to the other TAs of courses using Oracle this semester... The server name is ecom1.site.uottawa.ca, the port is 1521, and the sid should be siteacad (siteacad.uottawa.ca may also work). Your URL variable should look like this (you can try both): url="jdbc:oracle:oci8:@(description=(address=(host=ecom1.site.uottawa.ca)(protoc ol=tcp)(port=1521))(connect_data=(sid=siteacad)))" url="jdbc:oracle:oci8:@(description=(address=(host=ecom1.site.uottawa.ca)(protoc ol=tcp)(port=1521))(connect_data=(service_name=siteacad.uottawa.ca)))" In the example above, I use the 'fat' jdbc client, which depends on the Oracle net8 client being installed. To substitute for the thin JDBC client, I believe that the variable would become something like: url="jdbc:oracle:thin:@ecom1.site.uottawa.ca:1521:siteacad" Remember that ecom1 is not visible from outside of Campus, it is therefore not possible to access the siteacad database from external sites... Cheers! -- Michel Racine ------------------------------------------------------------------ > Hello, > > We have more or less completed our sql script. To maintain the Montoring > relation we thought of using an assertion to check that all coop > participations are mentored. When entering this into SQL*Plus, we get this > message: > > CREATE ASSERTION Check_Mentoring ( > * > ERROR at line 1: > ORA-00901: invalid CREATE command > > Do you have any idea why this is happening? In fact, many people asked this question and I verified: Oracle does not support assertions. You must try to do things with CHECK. One way around this would: whenever an assertion mentions n tables, you implement that assertioin by using n CHECKs. ------------------------------------------------------------------ > > For the weak entity set Employee --- dependents > ----children, is it possible that 2 parents of the same > children can be working in the company? If so, does > that change any of the notation of the weak entity? > Assume that the children will depend on only one of the parents. ------------------------------------------------------------------ > Is a co-op student to be considered an employee, or > is it a completely separate entity? In the > description, it does not say a co-op student is an > employee, but do we assume it is or no? My intention was not to: so a coo-op student is not an employee. ------------------------------------------------------------------ Subject: Re: FW: how to use Oracle at home On Wed, 1 Oct 2003, Iluju Kiringa wrote: > I just spoke with Michel this morning about that. He'll send us a mesage > during the day with some details about which settings to use for that. > Hello everyone, I have updated the online Oracle documentation to add two new sections: 1. How to configure the Oracle software at home. This section describes how to set up a server and configure the client. The material was produced by my TA of last year and is quite complete. Although it describes how to install from CD, the configuration step should be the same if the software has been dowloaded from the www.oracle.com site. It also explains how to configure the client from within campus using our server's parameters. 2. How to access SITE's Oracle server from home. The Oracle server is not accessible directly from outside of Campus. It would hence not be possible to install the Oracle client on a home machine, then point it to our server. It is only accessible directly from within campus. As a workaround, users that feel comfortable with Unix interfaces can follow the instructions in the section 'Connecting to SITE's Oracle server using Unix clients'. SITE users can connect to the ugate.site.uottawa.ca Unix server, and use the command-line interface described in that section to access our DBMS. [Michel Racine] ------------------------------------------------------------------ ------------------------------------------------------------------