One retyped invoice register becomes seven keyed tables, and the rebuilt sales figure still matches the ledger to the cent, in a Unit 4 table design exercise for AC442. Searches like "ac 442 unit 4 assignment example", "ac442 unit 4 sample" and "ac442 unit 4 example" land here.
What a finished AC442 Unit 4 table design exercise looks like
Four pages and a load summary. Page one reproduces six rows of the flat register as a figure, showing one distributor's name spelled two ways and a license number that lost its leading zero when the file was saved. Page two lists the functional groups found in the nineteen columns. Pages three and four specify seven tables, DISTRIBUTOR, SALES_REP, WINE, INVOICE, INVOICE_LINE, CASH_RECEIPT and CASH_APPLICATION, each as a grid of column, data type, null rule and key. Money is DECIMAL(12,2) throughout. The license is VARCHAR(20). Vintage is a nullable SMALLINT, so non-vintage blends store an honest blank instead of the text NV. INVOICE_LINE is keyed on invoice number and line number together. The load summary gives the row count for each table and the rebuilt sales total beside the ledger's.
How a AC442 Unit 4 example is structured
Evidence comes before design: the sample rows show the faults the tables exist to remove, so each later decision has a visible cause. Grouping the nineteen columns by what they describe, distributor, representative, wine, invoice, line and payment, is presented as the step that decides the tables, and each group names the column that determines the others. Specifications follow in dependency order, parents before children, so a reader can check every foreign key against a table already defined. Data types are argued wherever accounting meaning is at stake, as with currency and with identifiers that look numeric but are not. The invoice total is deliberately left out of storage and derived from its lines, and a short paragraph explains why: nine invoices in the register carried stored totals that disagreed with their own lines. Proof of losslessness closes the exercise.
Faults shown before fixes
Six register rows expose a retyped distributor name, a license stripped of its leading zero and two check numbers crowded onto one line.
Nineteen columns, six subjects
Columns are grouped by what they describe, and each group names the field that determines the rest, which becomes the basis for every table.
Seven specifications, parents first
Column, type, null rule and key appear for each table, ordered so every foreign key points at something already defined above it.
A total derived rather than stored
Nine invoices disagreed with their own lines by 1,137.50 combined; the lines tie to the ledger, so the stored total is dropped and recomputed.
Proof that nothing was lost
Row counts per table and a rebuilt 1,284,660.00 of distributor sales sit beside the general ledger balance, with the difference shown as zero.
Where marks go in AC442 Unit 4
Designs that split the register into tables without showing the split lost nothing are marked down most often, since an accounting reader needs the rebuilt total before trusting any structure. Choosing a floating-point type for money is a frequent error, and graders catch it quickly. Identifiers that look numeric, license numbers and ZIP codes, stored as integers lose their leading zeros and draw deductions. Repeating groups carried over as columns, check_1 and check_2, show the flat file's shape surviving into the design. A stored invoice total with no check against its lines invites the same disagreement the register already had. Keys declared without saying what makes them unique leave the design undefended. Specifications listed in random order, with a child table defined ahead of its parent, are harder to verify and lose organization credit.
Get a AC442 Unit 4 example written to your instructions
Attach the spreadsheet your Unit 4 prompt hands out, exactly as issued, plus the rubric and the database product your section uses if it names one, since data types differ between products. Tables, specifications and the rebuilt control total arrive within 24-48h, and the first custom sample is free.
AC442 Unit 4 questions, answered
Why not store the invoice total for speed?
Because a stored total can drift from its lines, and the register already proved it: nine invoices disagreed with themselves. Recomputing the total from lines costs almost nothing at this volume, and it guarantees agreement. Some sections accept a stored total if a constraint or a scheduled check compares it with the lines, and the sample notes that alternative in a sentence.
What happens to non-vintage wines?
Their vintage is stored as a blank rather than as the letters NV, which would force the column to text and break every sort and range filter on year. A null says honestly that no vintage applies. The specification records the rule, and the load summary counts how many SKUs carry a blank so a reader can check it.
How is the rebuilt total proven?
By summing line amounts in the new INVOICE_LINE table and placing the result beside the general ledger's distributor sales balance. Both read 1,284,660.00 in the sample. Row counts per table sit alongside, so a grader can see that 4,906 lines went in and 4,906 came out, with nothing duplicated or dropped along the way.