DAY 14: ACCESS CHAPTER 1 RAHUL KAVI October 8,

LAST LECTURE Introduction to Databases 2

ACCESS INTERFACE Navigation Pane Table Views: –Datasheet view (similar to Excel worksheet) –Design view (used to modify table) 3

TABLES Tables store data about a particular set. Contains fields and records. Fields are… Records are … 4

PRIMARY KEY The primary key uniquely identifies each record in a table. By default, tables have an ID field that is an autoincremented integer –The value of ID goes up by one for each new record 5

EXAMPLES OF PRIMARY KEYS (DEPENDING ON CONTEXT) Username in bank users table. ID in a contacts table. WVU Student ID in students table. Country domain id (.us,.in,.ch,.cn,.uk, etc.) in internet domains table. Facebook URL of CS101 class ( if making a tables of unique URLs. 6

NAVIGATION BAR Record navigation –Forward, Back –First, Last –Record number (position of the record, not primary key) New Record Search 7

FORMS Allows you to enter, modify, or delete table data This can also be done in the Datasheet view, but forms allow you to customize what fields are shown and even work with multiple tables 8

QUERIES Queries are questions you ask about the data Returns fields, or calculations on fields for records that match the criterion given 9

REPORTS Formatted information from tables or queries Access has are different tools for designing, modifying, and viewing reports 10

SAVING Word, Excel, and Powerpoint all work from memory –This means all changes are only stored in temporary storage until you save Access data works directly from storage –As soon as you finish adding/editing a record, the changes are written to disk Access design (of tables, forms, queries, and reports) works from memory –You must manually save any database design changes 11

UTILITIES- COMPACT AND REPAIR As you modify and delete records, not all of the space is reclaimed Compact and Repair reclaims that space by creating a new database, copying all definitions over, and finally copying the data over. Database Tools->Tools->Compact and Repair Database 12

UTILITIES- BACKUP File->Save & Publish->Back Up Database This creates a copy of the database, with the date added to the filename If you are about to try something new for the first time, especially if it involves deleting something, backup your database first so you have a good copy to fall back on if you mess up 13

FILTERING First, select the field you want to filter on Home->Sort & Filter->Filter Home->Sort & Filter->Selection can make common filtering easier Advanced filtering allows you to filter by multiple fields 14

SORTING Sorting changes the order of the records in a table Home->Sort & Filter-> Ascending, Descending Really, both filtering and sorting are special cases of queries Other queries can incorporate sorting and filtering techniques 15

ACCESS VERSUS EXCEL Excel is often easier if you are working with data with simple relationships As the complexity of your data increases, the need for a logical organization increases Access allows you to specify that organization 16

USE ACCESS WHEN YOU: Require multiple related tables to store your data Have a large amount of data Need to connect to and retrieve data from external databases Need to group, sort, or total data based on multiple parameters Need to allow multiple users to simultaneous modify the data 17

USE EXCEL WHEN YOU: Only need one worksheet to handle all of your data Have mostly numeric data Want to run “what if” analysis on your data Need to create complex charts and/or graphs 18

ACCESS IS RELATIONAL This means you can manage groups of data (tables) and set rules (relationships) about how those tables interact Relationships are defined in the Relationships Window using Join Lines 19

RELATIONSHIP WINDOW Database Tools->Relationships or Table Tools->Table->Relationships Add in the tables you want to join together Before you can create relationships, you must close the tables involved Drag line from the primary key in one table, to the foreign key in the other table 20

REFERENTIAL INTEGRITY Referential Integrity causes Access to ensure the record exists for the primary table before it can be referenced in the related table If Referential Integrity is enabled, Cascading of Updates and/or Deletes can be enabled –Delete of primary record deletes related record –Update of primary record ID updates related record’s foreign key 21

NEXT CLASS Database design –Required tables –Avoiding redundancy –Data type selection –Calculated fields –Keys Sharing data with Excel Relationship types 22