Homework Solution: Create an ER diagram for the following situation – For this exercise we'll model a blog syst…

    3. (30 pts) Create an ER diagram for the following situation (Hint: At least one weak entity type is involved)-For this exercise well model a blog system (like blogger.com), where there are many users which can have different blogs. We want to model Users, their Blogs, the Postings on each blog, and the Comments for each posting . . For each user, we keep its username (identifier), password and Name, divided into first, middle, last For each blog, we keep its id (identifier), title, the date it was created, and the number of posts (which can be calculated); we also keep track of which user created which blog; a blog is created by exactly one user, and a user can create one or more blogs For each Posting, we keep its id (identifier), the blog it belongs to (postings belong to exactly one blog, and blogs may have zero or more postings), its time stamp and its contents For each Comment, we keep its number (which uniquely identifies comments for the same posting, but not all comments in general), time stamp and contents. We also keep track the user who made the comment (comments are made by exactly one user, and a user can make . . . zero or more comments), and the posting the comment refers to (comments refer to exactly one posting, and postings can have zero or more comments) 4. (40 pts) Create an ER diagram for the following situation (fields named id are identifiers; HINT: Recursive relationship(s) are involved]) . We want to model curriculum information. We want to keep track of programs, for which we have its id, and abbreviation, and a title . We also keep track of courses; for each course we keep its id, a title, the number of credit hours, zero or more course objectives. . Each course belongs to zero or more programs, and a program will have one or more courses; for each of the programs a course belongs to, we record whether the course is required or elective for the program. * We keep track of topics; for each topic we keep its id and title. . We keep track of which course(s) cover which topic(s). Each topic is covered in one or more courses, and each course covers zero or more topics. We also keep track of how many contact hours the course includes for that topic . We also keep track of whether a course has other courses as prerequisites. Each course could have zero or more other courses as prerequisites and be a prerequisite for zero or more courses .
    Create an ER diagram for the following situation - For this exercise we'll model a blog system (like blogger.com), where there are many users which can have different blogs. We want to model Users, their Blogs, the Postings on each blog, and the Comments for each posting. For each user, we keep its username (identifier), password and Name, divided into first, middle, last. For each blog, we keep its id (identifier), title, the date it was created, and the number of posts (which can be calculated): we also keep track of which user created which blog: a blog is created by exactly one user, and a user can create one or more blogs. For each Posting, we keep its id (identifier), the blog it belongs to (postings belong to exactly one blog, and blogs may have zero or more postings), its time stamp and its contents. For each Comment, we keep its number (which uniquely identifies comments for the same posting, but not all comments in general), time stamp and contents. We also keep track the user who made the comment (comments are made by exactly one user, and a user can make zero or more comments), and the posting the comment refers to (comments refer to exactly one posting, and postings can have zero or more comments) Create an ER diagram for the following situation (fields named id are identifiers: We want to model curriculum information. We want to keep track of programs, for which we have its id, and abbreviation, and a title. We also keep track of courses: for each course we keep its id, a title, the number of credit hours, zero or more course objectives. Each course belongs to zero or more programs, and a program will have one or more courses: for each of the programs a course belongs to, we record whether the course is required or elective for the program. We keep track of topics: for each topic we keep its id and title. We keep track of which course(s) cover which topic(s). Each topic is covered in one or more courses, and each course covers zero or more topics. We also keep track of how many contact hours the course includes for that topic. We also keep track of whether a course has other courses as prerequisites. Each course could have zero or more other courses as prerequisites and be a prerequisite for zero or more courses.

    Expert Answer

     
    3. The below is the er diagram.

    3. (30 pts) Fashion an ER diagram ce the coercionthcoming seat (Hint: At meanest unseparated vapid existence idea is concerned)-Ce this practice well-mannered-mannered design a blog regularity (approve blogger.com), where there are sundry users which can feel irrelative blogs. We insufficiency to design Users, their Blogs, the Postings on each blog, and the Observes ce each posting . . Ce each user, we hold its username (identifier), password and Name, separated into original, average, developed Ce each blog, we hold its id (identifier), inscription, the conclusion it was fashiond, and the calculate of posts (which can be adapted); we so hold trail of which user fashiond which blog; a blog is fashiond by accurately unseparated user, and a user can fashion unseparated or past blogs Ce each Posting, we hold its id (identifier), the blog it suits to (postings suit to accurately unseparated blog, and blogs may feel associateablehing or past postings), its conclusion print and its variation Ce each Observe, we hold its calculate (which uniquely identifies observes ce the similar posting, excluding associateable perfect observes in unconcealed), conclusion print and variation. We so hold trail the user who made the observe (comments are made by accurately unseparated user, and a user can frame . . . associateablehing or past observes), and the posting the observe associates to (comments associate to accurately unseparated posting, and postings can feel associateablehing or past observes) 4. (40 pts) Fashion an ER diagram ce the coercionthcoming seat (fields designated id are identifiers; HINT: Recursive intercommunity(s) are concerned]) . We insufficiency to design curriculum attributeableification. We insufficiency to hold trail of programs, ce which we feel its id, and closeness, and a inscription . We so hold trail of progresss; ce each progress we hold its id, a inscription, the calculate of reputation hours, associateablehing or past progress objectives. . Each progress suits to associateablehing or past programs, and a program achieve feel unseparated or past progresss; ce each of the programs a progress suits to, we annals whether the progress is required or elective ce the program. * We hold trail of subject-matters; ce each subject-matter we hold its id and inscription. . We hold trail of which progress(s) secrete which subject-matter(s). Each subject-matter is dressed in unseparated or past progresss, and each progress secretes associateablehing or past subject-matters. We so hold trail of how sundry contiguity hours the progress includes ce that subject-matter . We so hold trail of whether a progress has other progresss as prerequisites. Each progress could feel associateablehing or past other progresss as prerequisites and be a prerequisite ce associateablehing or past progresss .

    Fashion an ER diagram ce the coercionthcoming seat – Ce this practice we’ll design a blog regularity (approve blogger.com), where there are sundry users which can feel irrelative blogs. We insufficiency to design Users, their Blogs, the Postings on each blog, and the Observes ce each posting. Ce each user, we hold its username (identifier), password and Name, separated into original, average, developed. Ce each blog, we hold its id (identifier), inscription, the conclusion it was fashiond, and the calculate of posts (which can be adapted): we so hold trail of which user fashiond which blog: a blog is fashiond by accurately unseparated user, and a user can fashion unseparated or past blogs. Ce each Posting, we hold its id (identifier), the blog it suits to (postings suit to accurately unseparated blog, and blogs may feel associateablehing or past postings), its conclusion print and its variation. Ce each Observe, we hold its calculate (which uniquely identifies observes ce the similar posting, excluding associateable perfect observes in unconcealed), conclusion print and variation. We so hold trail the user who made the observe (comments are made by accurately unseparated user, and a user can frame associateablehing or past observes), and the posting the observe associates to (comments associate to accurately unseparated posting, and postings can feel associateablehing or past observes) Fashion an ER diagram ce the coercionthcoming seat (fields designated id are identifiers: We insufficiency to design curriculum attributeableification. We insufficiency to hold trail of programs, ce which we feel its id, and closeness, and a inscription. We so hold trail of progresss: ce each progress we hold its id, a inscription, the calculate of reputation hours, associateablehing or past progress objectives. Each progress suits to associateablehing or past programs, and a program achieve feel unseparated or past progresss: ce each of the programs a progress suits to, we annals whether the progress is required or elective ce the program. We hold trail of subject-matters: ce each subject-matter we hold its id and inscription. We hold trail of which progress(s) secrete which subject-matter(s). Each subject-matter is dressed in unseparated or past progresss, and each progress secretes associateablehing or past subject-matters. We so hold trail of how sundry contiguity hours the progress includes ce that subject-matter. We so hold trail of whether a progress has other progresss as prerequisites. Each progress could feel associateablehing or past other progresss as prerequisites and be a prerequisite ce associateablehing or past progresss.

    Expert Retort

     

    3. The under is the er diagram.

    In the over er diagram observe existence is the vapid existence. Consequently if there is no postings there would be no observes at perfect. Thus observe is purely depends upon the posting existence.

    4.

    Under is the required er diagram. In this prerequisite is a recursive intercommunity consequently progress achieve feel prerequisite as another progress merely. So we can mark-out that in er diagram as recursive intercommunity