Database Fundamentals and Access Basics
Database Components
What Are Databases Made Of?
- Fields and records
What Is a Table?
Tables are the most basic object of a database; they store data in categories.
What Is a Field?
The basic unit of a database. The names of fields cannot start with a space or special characters. They cannot include periods, exclamation marks, or brackets. However, they may contain spaces in the middle. The field description allows you to clarify the information contained in the field name. The field type allows you to specify the type of information that will be entered in that field.
What Are the Types of Fields?
- Text: Allows you to store any type of text, including letters, numbers, and special characters. The default length is 50 characters; the maximum number of characters allowed in a text field is 255.
- Memo: Is used to store texts longer than 255 characters like comments or explanations. The maximum number of characters allowed in a memo field is 65,536 characters.
- Number: For numeric data used in calculations.
- Date / Time: To enter dates and times. Dates can be from year 100 to year 9999.
- Currency: To enter monetary data and numeric data used for calculations that contain between 1 and four decimals. Up to 15 digits to the left of the decimal point and four digits to the right can be used.
- AutoNumber: A unique sequential number (in increments of one), or a random number that Microsoft Access assigns every time a new record is added.
- Yes / No: Yes and No values, and fields that can store only one of two values (Yes/No, True/False, or On/Off).
- OLE Object: It is an object such as a Microsoft Excel spreadsheet, a Microsoft Word document, graphs, images, sounds, or other binary data.
- Hyperlink: Text or a combination of text and numbers stored as text and used as a hyperlink address.
- Record: The information contained about a person or an object.
Access Templates and Getting Started
What Is a Template?
Templates are predefined databases designed with the user’s needs in mind.
Getting Started Page: Right-Hand Panel
You can name the database that you will work on. This panel also contains the download button.
Advantages of Changing Database Format
- To create safer Access databases, to make them more compact, to make data recovery more reliable.
Why Update Databases from Previous Versions?
So it can be safer, smaller, and easier to recover if needed.
Table Templates and Relationships
What Are Table Templates Available For?
They are available for common items like contacts, issues, and tasks.
Steps for Creating a Table Template
- In the Create tab, in the Tables group, click Table Templates to open the menu.
- Click Contacts. A new table is created with the fields for contacts.
- In the Table Templates menu, click Tasks. A new table with the fields for tasks is created.
- In the Table Templates menu, click Issues. A new table with the fields for issues is created.
What Is a Foreign Key?
The foreign key is used to reference data in the primary key to avoid redundancy.
Types of Database Relationships
- One-to-one
- One-to-many
- Many-to-many