| Course | BU 453 Database Management |
|---|---|
| Unit | Unit 1 |
| Paper type | Requirements to entities exercise |
| Length | About 890 words, 6 pages |
| Format | APA 7 student paper |
| School | Herzing University |
| Program | BS in Business Analytics |
| Updated | September 2026 |
Free sample paper for BU 453 Unit 1
Ten Sentences, Nine Entities, Every Decision Quoted: A Requirements to Entities Exercise for a Composite Boise Music School's Lessons, Rentals and Recitals
Student Name
Business, Herzing University
BU 453: Database Management
Instructor Name
January 14, 2026
Ten Sentences, Nine Entities, Every Decision Quoted: A Requirements to Entities Exercise for a Composite Boise Music School's Lessons, Rentals and Recitals
The Business Narrative
Harmony Hill Music School, a composite business created for this course, teaches private music lessons in Boise, Idaho, rents instruments to its students and holds recitals. The owner described the business in the paragraph below, which is the only requirements document for the database. Each sentence is numbered so that every modeling decision can cite the sentence behind it.
(S1) We have about 380 students, children and adults, and 14 teachers. (S2) Each student takes a weekly lesson with one teacher on one instrument, at a fixed day and time, in one of our nine rooms, for a term; some students take two instruments with different teachers. (S3) Terms run fall, spring and summer, and lessons are 30, 45 or 60 minutes. (S4) For students under 18 we need a parent or guardian as the contact and the person who pays, and some children have two guardians who both want to be contacted. (S5) Some families have three children enrolled, and we bill the family once a month. (S6) We rent about 120 instruments, each with a serial number, and we need to know who has each one and since when. (S7) An instrument can be rented many times over the years, but only to one student at a time. (S8) We record whether each lesson happened, was canceled by the student or by the teacher, so we can arrange make-ups. (S9) Three times a year we hold a recital, and each performer plays one piece, which we list in the program with the composer. (S10) Teachers are paid by the hour taught, so we need their hourly rate.
Method
The exercise reads the narrative for the nouns the business keeps records about and tests each candidate with three questions. Does the business need to store several facts about it? Can there be many of it, each needing to be told apart? And does it exist independently of other things, or is it merely a description of something else? A noun passing all three becomes an entity with an identifier; a noun that only describes another becomes an attribute. Chen (1976), who introduced the entity-relationship model, describes an entity as a thing that can be distinctly identified, and the tests put that definition into practice. Hoffer et al. (2019) warn that the commonest early mistake is treating attributes as entities or the reverse, so each borderline case below is argued rather than assumed.
The Entities
Nine entities survive the tests. Each has an identifier, its attributes and the sentences that justify it.
| Entity | Identifier | Attributes | Justified by |
|---|---|---|---|
| Student | student_id | first name, last name, birth date, email, phone | S1, S4: students are counted and their age matters |
| Guardian | guardian_id | first name, last name, email, phone, relationship | S4: guardians are contacts with their own details; a child may have two |
| Billing account | account_id | account name, billing email, billing address | S5: the family is billed once, so the payer is not always one person |
| Teacher | teacher_id | first name, last name, email, phone, hourly rate, instruments taught | S1, S10: teachers are counted and paid by rate |
| Room | room_id | room name, capacity, has piano | S2: nine rooms, each lesson assigned to one |
| Term | term_id | season, year, start date, end date | S2, S3: enrollments last one term |
| Enrollment | enrollment_id | instrument, weekday, start time, lesson minutes | S2, S3: a student's weekly lesson with one teacher in one room for a term |
| Lesson | lesson_id | date, status (held, canceled by student, canceled by teacher, make-up) | S8: each lesson's outcome is recorded |
| Instrument | serial_number | type, make, size, condition, monthly fee | S6: each rented instrument has a serial number |
Two further record types, rentals and recital performances, are also needed, but they are best understood as relationships that carry their own facts; they are identified here and modeled fully in the diagram. A rental links one instrument to one student with a start date and an end date (S6, S7). A performance links one student to one recital with a piece and a composer (S9). Recital itself is an entity with a date and a venue, which brings the total to ten record types.
Borderline Decisions
Four decisions could have gone the other way. Guardian became an entity rather than a pair of attribute columns on Student because S4 says a child may have two guardians who both want contact, and S5 implies one guardian may have several children; storing guardians inside the student record would repeat a parent's details for each child and could not hold a second guardian cleanly.
Billing account became an entity separate from Guardian because S5 says the family, not a person, is billed. An adult student pays for themselves, a family with three children pays once, and in two families a grandparent pays while the parents are the contacts. Linking invoices to an account rather than to a guardian handles all three.
Instrument taught is an attribute of Enrollment, not an entity. The school needs no facts about violin as such beyond its name, and S2 says the instrument belongs to the lesson arrangement. Teachers' instruments are recorded as a list attribute for now, noted for review in normalization.
Lesson is an entity separate from Enrollment because S8 records the outcome of each individual lesson. Enrollment is the standing arrangement; Lesson is each week's occurrence of it.
What the Narrative Leaves Out
Several things the database will need are not in the narrative, and each is recorded as an assumption to confirm with the owner rather than invented silently. The narrative does not say how payments are recorded against invoices, so a payment record is assumed. It does not say whether a teacher's hourly rate changes during a term; the model assumes one rate per teacher, with history to be added if needed. It does not say whether recitals include teachers performing; the model assumes students only. And it does not say how long rental history must be kept; all history is kept. Codd (1970) argued that a database should represent the facts of the business independently of how any program uses them, which is why these gaps are raised as questions about the business, not settled by what would be convenient to program. Harmony Hill and its narrative are composites for this course.
References
Chen, P. P.-S. (1976). The entity-relationship model: Toward a unified view of data. ACM Transactions on Database Systems, 1(1), 9-36. https://doi.org/10.1145/320434.320440
Codd, E. F. (1970). A relational model of data for large shared data banks. Communications of the ACM, 13(6), 377-387. https://doi.org/10.1145/362384.362685
Hoffer, J. A., Ramesh, V., & Topi, H. (2019). Modern database management (13th ed.). Pearson.
The Herzing BU 453 Unit 1 instructions
The opening BU 453 unit asks students to read a business scenario and identify the entities a database must store. Typical requirements include listing each entity with its attributes and a unique identifier, explaining how entities were separated from attributes, and tying decisions to the scenario text. Many instructors ask what to do when the scenario leaves something out; the usual answer is to state an assumption rather than invent facts silently. Students are generally discouraged from modeling their own workplace instead of the given case. A table of entities with justifications is standard, supported by short APA 7 discussion of borderline decisions, and it becomes the foundation for the diagram in the next unit.
How this BU 453 Unit 1 example is built
The paper begins by quoting the owner's narrative with numbered sentences so every decision can cite one. A method section sets out three tests for deciding whether a noun is an entity, citing the origin of the entity-relationship model. A table lists nine entities with identifiers, attributes and justifying sentences. A short passage identifies rentals and recital performances as relationships that carry facts, bringing the count of record types to ten. A section argues four borderline decisions, including guardian as an entity and instrument taught as an attribute. The final section lists what the narrative leaves out and records each gap as an assumption to confirm.
BU 453 Unit 1 rubric: what full points look like
Herzing's rubric for the requirements to entities exercise usually rewards correct identification of entities, appropriate attributes and identifiers, traceability to the scenario, sound handling of borderline cases and explicit assumptions, with the quality of writing also scored. Identification earns full credit when every thing the business keeps records about is found and nothing that is merely a description is promoted to an entity. Identifiers score highest when they are genuinely unique and stable. Traceability rewards citing the scenario sentence behind each decision. Borderline cases are judged on reasoning, not on the choice alone. Assumptions earn points when gaps are named rather than filled invisibly, since a hidden assumption becomes a design flaw later.
BU 453 Unit 1 help before you submit
Entity exercises often lose points by turning every noun into an entity, including descriptions such as color or instrument type that belong as attributes. Another common problem is missing identifiers, or using names, which are not unique, as keys. Students frequently skip the link to the scenario, so decisions look arbitrary. Some merge distinct things, such as the person who pays and the person contacted, because the scenario mentions them together. Others ignore facts that appear only once in the narrative, such as recital pieces. Many fill gaps with invented details instead of stated assumptions. Finally, modeling your own employer instead of the assigned scenario can reveal internal information and makes grading against the case impossible.
Get a BU 453 Unit 1 example written to your instructions
The instructions and rubric from your BU 453 classroom are the starting point, along with the scenario the assignment supplies. The custom example lists candidates with their source phrases, records what was rejected and why, fixes an identifier for each entity, keeps attributes to a single fact and closes on stated assumptions. First custom sample free, returned in 24 to 48 hours.
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BU 453 Unit 1 questions, answered
How do I tell an entity from an attribute?
Ask whether the thing has facts of its own that the business records. A color usually does not and belongs to whatever it describes; a supplier usually does, since somebody keeps an address and a contact for it. Where the scenario records only one fact about something today but plainly treats it as a thing, say so in the assumptions and choose deliberately rather than by feel.
What if the scenario leaves something out?
Assume, record the assumption and move on. A narrative of a few paragraphs cannot describe a whole business, and every model built from one rests on things the writer did not say. What separates a strong submission is that the gaps are listed where a marker can find them, with the reading you chose, rather than filled in quietly and discovered later when the schema will not hold.
Could I model my own workplace instead of the given scenario?
Only if the instructions invite it, and even then keep the organization unnamed and the details invented. Requirements gathered on the job describe how a real company runs, which is competitive information whether or not anybody labeled it that way. The supplied scenario exists so the graded artifact can be shared, kept and compared without any of that hanging over it.
Where can I find a free BU 453 Unit 1 sample paper?
The complete BU 453 Unit 1 requirements to entities exercise is published above at no charge, with the numbered narrative, the entity table and margin notes. Working from a different scenario? Send it along and an entity analysis for it is prepared free, generally within two days.
How do I tell an entity from an attribute in BU 453 Unit 1?
Ask whether the business stores several facts about the thing and needs to tell many of them apart. The sample keeps guardian as an entity because each has contact details and some have several children, but treats instrument taught as an attribute.