INSY 2301 Study Guide - Final Guide: Elementary Arithmetic, Unique Key, Referential Integrity
22 Jun 2018
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Relational Database Management Systems
Data is organized into tables with links formed by common fields
Benefits:
oAbility to easily add, change, and delete data
oAbility to run queries answering questions about the data
oAbility to produce professional-looking formatted reports
oProtection of database through security, control, and recovery functions
Primary Key: A field whose values uniquely identify records in a table
oNo value in a primary key field can repeat
oPrimary key included in a table to form a relationship becomes a foreign key
Working with Tables
Fields and records can be directly added to a table in datasheet view
A field’s data type determines which type of data can be entered
oAutoNumber: Automatically inserts a unique number for each record
oShort Text: Allows letters, digits, and other characters
oDate/Time: Allows a variety of date and time formats
oYes/No: Represents one of two options - true/false, yes/no, on/off
Field names shouldn’t contain spaces; a caption is used to display a different name in
database objects
Properties of fields can be edited in design view
oIncludes ability to designate a primary key
Data can be exported from Excel, other Access tables, text files, etc. into tables
Defining Relationships
One-to-many relationship exists when one record in the first table (primary table)
matches zero, one, or many records in a second table (related table)
Enforcing referential integrity between related tables makes it possible to update data
across tables from one place
Working with Queries
Query is a question asked about data in a database
Access is able to…
oDisplay certain fields/records from table(s), based on specified conditions
Comparison Operators: Act as the conditions for records to be shown
AND Logical Operator: Displays records only if two or more
conditions are met
OR Logical Operator: Displays records if at least one condition is met
oSort records (by up to 10 sort fields - primary, secondary, and so on)
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