tag:blogger.com,1999:blog-6393051114813114443.post1673625679515837374..comments2024-01-24T15:38:09.758-05:00Comments on Lee's Blog: An Entity Relationship Diagram ExampleLee Richardsonhttp://www.blogger.com/profile/01314803491511307042noreply@blogger.comBlogger74125tag:blogger.com,1999:blog-6393051114813114443.post-65648700876903685132014-07-16T20:56:50.712-05:002014-07-16T20:56:50.712-05:00This comment has been removed by a blog administrator.Anonymoushttps://www.blogger.com/profile/14484325262680339103noreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-86932783534305768772014-06-26T20:37:12.769-05:002014-06-26T20:37:12.769-05:00This comment has been removed by a blog administrator.Anonymoushttps://www.blogger.com/profile/14484325262680339103noreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-8014535814269309512014-06-03T21:22:58.485-05:002014-06-03T21:22:58.485-05:00This comment has been removed by a blog administrator.Anonymoushttps://www.blogger.com/profile/07678511547613608303noreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-51511176116687052662014-05-31T22:45:57.478-05:002014-05-31T22:45:57.478-05:00This comment has been removed by a blog administrator.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-159077538657133592014-05-25T09:38:11.023-05:002014-05-25T09:38:11.023-05:00It should be noted that the physical implementatio...It should be noted that the physical implementation is wrong. The relationship from Project to ProjectEmployee should be 1:1,M not 1:0,M.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-53962402229290088052014-03-27T18:37:17.478-05:002014-03-27T18:37:17.478-05:00This comment has been removed by a blog administrator.Anonymoushttps://www.blogger.com/profile/14484325262680339103noreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-24440916404417093752014-03-20T03:45:20.963-05:002014-03-20T03:45:20.963-05:00That's a good refresher... it reminded me a lo...That's a good refresher... it reminded me a lot.<br />thanks for that.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-85270458994052614202013-10-12T03:47:05.129-05:002013-10-12T03:47:05.129-05:00Thanks for the refresher!Thanks for the refresher!maestrohttps://www.blogger.com/profile/12039798071148882919noreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-59249427479700259172013-10-12T03:46:05.955-05:002013-10-12T03:46:05.955-05:00Nice article. A good refresher!Nice article. A good refresher!maestrohttps://www.blogger.com/profile/12039798071148882919noreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-46716527205296834762013-01-25T08:53:15.081-05:002013-01-25T08:53:15.081-05:00Ui would like to ask what do you call the word ins...Ui would like to ask what do you call the word inside the ENTITY and RELATIONSHIP? thanks..:)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-43012624881333040822012-06-16T23:09:07.701-05:002012-06-16T23:09:07.701-05:00Awesome! I wish you were my Software Engineering t...Awesome! I wish you were my Software Engineering teacher :DOmar Tariq Jutthttps://www.blogger.com/profile/10528122893213662278noreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-848655037590849452012-05-08T09:02:58.696-05:002012-05-08T09:02:58.696-05:00Nice post brother, can you please send me the refe...Nice post brother, can you please send me the reference on what base you written this? I am preparing a paper and I need to know the root. Please give me a reference.Shabab Haider Siddiquehttps://www.blogger.com/profile/14896191923433512555noreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-18619092823468675852012-03-01T15:49:44.290-05:002012-03-01T15:49:44.290-05:00THANKS.NICE ARTICLE.THANKS.NICE ARTICLE.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-74930515626448716192012-01-29T12:59:49.239-05:002012-01-29T12:59:49.239-05:00Can any one please tell me how to construct databa...Can any one please tell me how to construct database tables in RAD? Is is possible in the first place? Please let me know.<br /><br />Abhishek N.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-52418496722386203202012-01-29T11:10:54.182-05:002012-01-29T11:10:54.182-05:00Great post. Here’s a tutorial that shows how you c...Great post. Here’s a tutorial that shows how you can easily build an online database-driven web application with a parent-child table relationship, without codinghttp://blog.caspio.com/web-database/creating-one-to-many-relational-datapages/Scott Levyhttps://www.blogger.com/profile/15982269383206033516noreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-17482968262492757932011-10-02T10:48:20.862-05:002011-10-02T10:48:20.862-05:00Smashing! Damn! Your good! I wish that our profess...Smashing! Damn! Your good! I wish that our professors are as good as you! Thanks a lot on this ERD!<br /><br />-an intuitive student from PhilippinesAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-88066061656008325972011-09-08T06:49:49.381-05:002011-09-08T06:49:49.381-05:00As one with 25 years + system analytical and data ...As one with 25 years + system analytical and data modelling experience (both business and public) I would emphasize the following regarding Mr Reston’s piece:<br />1) his usage of ‘can’ to mean either ‘may’ (see example 1 ‘zero thru many’ and example 4 ‘zero or one’) or ‘must’ (see example 2 ‘one thru many’ and example 3 ‘one only’) is misleading and bewildering, especially for those relatively new to data modelling<br />2) his usage of the following symbols is both redundant and contrary to accepted data modelling practice:<br /> - the double dash to denote the mandatory existence of one entity occurrence involved in a relationship with one or more other entity occurrences; instead, the use of a single dash without the crows feet symbol (used to indicate multiple occurrences) next to it is the norm<br /> - the use of a single dash to denote a single entity occurrence whether optional or mandatory; data modellers typically just leave out the crows feet symbol to do this and only use (see comment above) the single dash to indicate that the occurrence is mandatory, not if it’s optional <br /> - the use of ‘O’ to denote only a zero entity occurrence; the normal practice is to use ‘O’ only to indicate whether the occurrence or occurrences of that entity are optionally (i.e. zero, one or more occurrences) related to another entity<br />3) his failure to mention that the presence of an associative or link table in many-to-many type relationships in a physical model is also common practice in the design of a logical model (where tables are called entities and where such entities may contain unique attributes) <br />4) his use of a broken rather than an unbroken line linking related entities in the examples could do with explanation – why?Jeremy Maynoreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-65085018722023052742011-05-05T03:31:49.499-05:002011-05-05T03:31:49.499-05:00Thanks alot! Your explanation was clearer than my ...Thanks alot! Your explanation was clearer than my textbook! Keep it up! :)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-34732165337277415392011-03-28T06:50:13.567-05:002011-03-28T06:50:13.567-05:00Thanks a lot...
the clearer the better...
keep...Thanks a lot...<br /> the clearer the better...<br /> keep up!...Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-56141063460452761062011-02-20T12:39:57.233-05:002011-02-20T12:39:57.233-05:00This really helped me. I'm a beginner or you c...This really helped me. I'm a beginner or you can say 'just learned' about DBMS theory. Thanks for this example Lee.KokaLahttp://imaskingforit.blogspot.com/noreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-1357610169132357702010-12-21T08:55:46.301-05:002010-12-21T08:55:46.301-05:00How should I interpret the relation between projec...How should I interpret the relation between project and TechnologyProject? I mean, in daily practice, on what field they should be related to eachother? A column ProjectType in the entiry Project?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-62575519049616670122010-12-14T12:59:52.627-05:002010-12-14T12:59:52.627-05:00Hey guys,
First of all I would like to thank Lee....Hey guys,<br /><br />First of all I would like to thank Lee. He has pointed a very useful and important topic about ER diagram, I found what exactly I was looking for and searching. I am doing my bachelor in CS and I think I will need more help .Zubair Mhttps://www.blogger.com/profile/02321688685314627389noreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-81020520779258956522010-03-06T14:38:01.745-05:002010-03-06T14:38:01.745-05:00Thanks brother, a very nice and simple example to ...Thanks brother, a very nice and simple example to understand.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-91478777334240970192009-10-27T00:59:16.921-05:002009-10-27T00:59:16.921-05:00I have a question on the phsical diagram.why u put...I have a question on the phsical diagram.why u put minimum value of 0 in the project-projectEmployee relationship? it is not clear for me.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6393051114813114443.post-37295645873913908572009-10-19T06:32:45.300-05:002009-10-19T06:32:45.300-05:00Hi Lee,
I am a newbie into the world of databases....Hi Lee,<br />I am a newbie into the world of databases. Could you help me given the scenario described below:<br /><br />Consider the following set of requirements for a university database that is used to keep track of students' transcripts. <br /><br />a. The university keeps track of each student's name, student number, social security number, current address and phone, permanent address and phone, birthdates, sex, class (freshman, sophomore, ... , graduate), major department, minor department (if any), and degree program (B.A., B.S., ... , Ph.D.). Some user applications need to refer to the city, state, and zip code of the student's permanent address and to the student's last name. Both social security number and student number have unique values for each student. <br /><br />b. Each department is described by a name, department code, office number, office phone, and college. Both name and code have unique values for each department.<br /><br />c. Each course has a course name, description, course number, number of semester hours, level, and offering department. The value of the course number is unique for each course.<br /><br />d. Each section has an instructor, semester, year, course, and section number. The section number distinguishes sections of the same course that are taught during the same semester/year; its values are 1,2,3, ... , up to the number of sections<br />taught during each semester.<br /><br />e. A grade report has a student, section, letter grade, and numeric grade (0, 1, 2, 3, or 4).<br /><br />Question: <br />Design an ER schema for this application, and draw an ER diagram for that schema. Specify key attributes of each entity type, and structural constraints on each relationship type. <br /><br />Note any unspecified requirements, and make appropriate assumptions to make the specification complete.Unknownhttps://www.blogger.com/profile/05933732946655083566noreply@blogger.com