Video Rental Store M.S. Access Module CAS 133 Basic Computer Skills/MS Office Russ Erdman

Video Rental Store What are some of the Tables in the video store? Video Store InventoryCustomersEmployeesFinancial Database Tables You may have sub-categories and have to break them down and create more tables. In Access DB everything is based on the tables. Without the tables you can’t do anything. Queries are based on tables; reports are based on tables or queries.

Video Rental Store Relationships of the Tables: 1 and 2 – Customers rent videos 1. One customer can rent many videos } Two way relationship 2. One video can be rented by many customers 1 and 4 1. One customer pays to rent 2. Customer owes money 3. Customer overpays (accounts receivable) 1 and 3 1. Employees get a deal and can rent at a discount or for free – may involve financial table Potential Relationships: 2 and 3 1. Employee could be a customer 2. Incentive program based on how many customers (new?) you get to rent videos

Video Rental Store Before you start any database design there are a couple of rules – things to know. 1.Purpose of the design – in our case to get a grade, but ostensibly to manage issues in a video store. 2. Always design on paper first – create a flow chart. 3. Determine what the fields will be for every table - Try to determine what some of the fields are for the tables, such as, the Inventory Table. Three things you have to know about fields to design DB: 3a. Field Name 3b. Field type 3c. Field Length

Video Rental Store 3a. The fields should make sense and be logically distinct from each other (Last and First Name – should they be split apart or does it matter?) 3b. Every table has a unique field or Primary Key (This is a very important field type. Also, you can’t do math on text and you can’t mix text and numbers in a number data type.) 3c. Field length – it is important in Access to know how long is the field length, that is, how many characters you can put into that field. Default length is 50, can go to 64 characters. Why field length? Question: How long does the Title field have to be? A logical answer might be: As long as it needs to be for the longest title of a video. If default is 50, then each time a record is input it takes up as much space in bytes (characters) as has been allowed (in this case 50) no matter how long the actual title is up to the 50 characters. Access database file can become radically large because of this storage process. You should abbreviate where possible.

Video Rental Store What are some field possibilities? We will limit our table to 10 fields: Title Category Actors (first two only full names) Director MPAA Rating Running Time (minutes) Year Format (DVD) BW/Color (BW) ID Number (Auto number) What are some Category field suggestions: this will vary depending on what movies we have, but might include: Comedy, Drama, Action, Sci-Fi, Self Help, Documentary, Family, Musical, Foreign, Classic, Horror.

Video Rental Store LETS GET STARTED Create Database - Start – Programs – Office – Access - choose Blank Database – save it and name it Video Store Create Tables – we will create just one table called Inventory using design view. Design Area – you need to specify a few things in the design area when you are creating the table. Validation Rule: Specify a rule – must be under the area the rule is to apply to, such as MPAA Rating. The validation rule won’t let you enter any data that doesn’t qualify, so if you misspell the rule then you have to know how to misspell the data. You can’t move on until you enter correct data or leave the field data box empty. Validation Text: Write the error message you want to appear if the wrong data is entered.

Video Rental Store Set field size – If you try to enter more data than the field size allows and you don’t have a validation rule, you will just run out of room to enter data. Data entry – after creating the tables you then can enter your data. Data is automatically saved to the DB as you enter it and move to the next field box. Why save automatically? DB is usually used by multiple people across a network. DB records save as you go so others can immediately access the record. As long as you are in entry mode (little pencil) no one else can use that record and see the updated table Also prevents loss of data if system crashes. Adjust the field width to accommodate your entries (You can double-click to resize just like in Excel).

Video Rental Store Field Name Field Length Field Type Title 30 (default is 50) Text *Category 11 (Documentary is longest) Text Actors (first two only full names) 30 Text Director 25 Text *MPAA Rating 5 Text Running Time (minutes) (don’t need to specify with numbers) Number Year (don’t need to specify with numbers)Number **Format (DVD) 1 Yes/No **BW/Color (BW) 1 Yes/No ID Number (Auto number) Auto number *categories have a limited number of characters for the field or you can tell the length to use, such as, G, PG, PG-13, R, NR, which are predefined lengths or limit the number of choices you can make. **Formats: DVD or VHS Only two choices, one or the other. Make the format one of the two and then a check means Yes and a null (no entry) means No. DVD checked VHS not checked BW checked Color not checked Go with the choice that is less common so less often will you have to enter a data (check) mark.

Video Rental Store Queries and Reports Queries: Based on tables, but they can be based on other queries. Allows us to ask a question of the database.  For example, sort alphabetically by title or list movies over 2 hours long. Queries are live data, if you change the table, the change affects the query and vice versa. Don’t delete data in a query as it will affect the table as well. Queries are very powerful. Queries are dynamic. Don’t use the wizard to create, use design view – at first it can be confusing, but easier as you learn it. Create in design view then run it to see if you got the desired results. RUN the query using the run button on the design view toolbar – this is the best way to run the query – it avoids confusion.

Video Rental Store Queries (cont.): Ways to add fields to query:  Double click on a field and it will jump to the next available field position.  Drag and drop – if drag on top of a field that is already there, the field will move over for the new one.  * means use all fields Don’t accidentally add a second copy of the table – this can mess up the query when you run it. Don’t use fields twice either. In the query design view the PK will appear as bold. Query by Example – grid is where you layout fields needed for your query. They need to be in the order they should appear when you run the query.

Video Rental Store Reports: Used to communicate database information at meetings, with customers or clients, etc. Use Report Wizard  Easy to use, similar to Chart Wizard in Excel.  Allows you to create a pretty picture at the end. Don’t use design mode, it is hard to control. You can use either tables or queries or both for a report. You can choose from more than one query or table for your report. You only want the fields you need for the report.

Video Rental Store STOP!