Database Systems. DBMS MS Access
What is "required"
Indicates that some data must be entered in the field before the record can be saved.
What is a foreign key
It is the "Primary Key" of a table which exists in a joint table
What's an example of a DBMS
MySQL Microsoft Access SQL server
What are the different types of relationships
One to one A record in one table relates to one and only one record in a second table • Primary key value from one table only exists once in the second table as a foreign key One to many • A record in one table may have more than one related record in a second table • Primary key value in the first table may be used several times in the second table Many to many Many records in table 1 are related to many records in table 2
Rules of database theory
Reduce redundancy and Inconsistency • Eliminate entering data multiple times; this will reduce potential for entering same data incorrectly Facilitate Maintenance • Need to accurately change data (ideally once) Maintain Accuracy • Relationships can help reduce potential for errors Simplify Information Retrieval • Extracting information should be easy and quick
What is input mask?
Specifies how a field looks as the user enters data into it
What is the first database object to be created
Tables
What are the database components
Tables Forms Reports Queries
What is format
The way text appears on a page.
What is indexed
Use to set a single - field index.
What is field size
indicates the maximum length of a data field
What is a database?
organized collection of data that can be easily accessed, retrieved, managed and updated
What is validation text
specifies the text in the error message that appears when a user violates a validation rule
Why are primary keys important
• Allows relationships between tables • Enforces the integrity of the table • Avoid administrative confusion in entering the data
What is datasheet view?
Allows you to add/enter, edit, delete, and search for data in a spreadsheet - like environment This is where you enter/input the records to your database tables
What is design view
Allows you to modify the design of new and existing tables
What is default value
Assigns a value that Access inserts into the field in each new record you add to the table.
What is validation rule
Checks the data entered against a criteria to prevent invalid or incorrect entries.
What is a database management system (DBMS)?
Database Management System (DBMS) is a software designed to store, retrieve, define, and manage data in a database.
What is decimal places
Determines how many decimal places are displayed and printed in number and currency fields
What is allow zero length
Determines whether a zero length strings are not valid entries
Flat File vs Relational Database
Flat file contains one single table Relational has multiple tables with relationships
Referential integrity
1. You cannot add a record to a related table unless there is already a matching record in the primary table 2. You cannot delete a record from a primary table while matching records still exist in the related table
What is a primary key
A column or set of columns in a database table that serves as a unique identifier. It is a key in a relational database that is unique for each record
Why are forms useful
Easy way to guide people into entering data correctly • With forms, it's possible to enter data into multiple tables at once, all in one place
What are the different types of field properties
Field size Validation rule Validation text Input mask Caption Format Decimal places Default value Required Indexed Allow zero length
What are database forms
Forms are used for entering, modifying, and viewing records from a table or a query
What is caption
Gives a label for access to use in reports and forms
What are queries
Queries are a way of searching for and retrieving specific data from one or more tables
What is a record
Records refers to rows, or horizontal groupings of unique field data.
What are database reports
Reports offer you the ability to present your data in print
What is a field
Set of data values, of the same data type. Referred to as a column or an attribute
What are the different data types
Short text Long text Number Currency Yes/No Date/Time Autonumber
What are tables
Tables are database objects that contain or hold all the data in a database
Why are reports useful
Useful because they allow you to present components of your database in an easy - to - read format • Reports can be created from a table or a query