Database Essentials: Components, Data Types, and Relationships

Database Fundamentals

A database is a set of tools designed to manage information related to a specific topic, such as books or CDs.

Core Database Components

• Tables

  Tables store data in an organized manner, featuring fields that allow information to be handled effectively.

• Queries

  Queries are tools that provide answers to questions that may arise about the stored data.

• Forms

  Forms are data objects that present information differently from a table, offering a more pleasant, colorful, and effective user interface.

• Reports

  Reports allow you to print stored data in formats designed by the user.

Understanding Data Types

Data types define the kind of values a field can hold. Here are common data types:

• Text (VARCHAR)

  Can be formed by letters, numbers, and spaces, up to a maximum of 255 characters.

• Memo Text (LONGTEXT)

  Similar to text fields, but with the special characteristic of being able to contain much more characters.

• Number

  These are numeric values, allowing mathematical operations. There are several types that differ in their nature (integer or decimal) and precision.

• Date/Time

  Fields declared with this type store data for dates and times.

• AutoNumber (Access Specific)

  Data in these fields (only valid for Access) is automatically inserted by the program, typically by incrementing the last record's content by one unit. This type of field is achieved by declaring an integer type and activating its "AutoValue" property.

• Yes/No (Boolean)

  These fields only accept "yes" or "no" (true or false) values.

• Object

  This data type is assigned to fields that will contain data of different natures, such as images, documents, or sounds.

• Hyperlink (Access Specific)

  Such data (valid in Access) refers to the paths of files located on your computer, other networked servers (on a local network or intranet), or Internet URLs themselves.

• OLE Objects

  Multimedia objects embedded within a database.

Database Relationships

Relationships define how tables are connected to each other. Here are the main types:

• One-to-One Relationship

  A single record in one table is related to exactly one record in the related table.

• One-to-Many Relationship

  A single record in one table can be related to several records in the related table. For example, this relationship exists between "Books" and "Loans" tables, as one main table record (a book) can be related to several loan records (a book may have been borrowed multiple times).

• Many-to-Many Relationship

  In this case, a record in one table can be related to many records in another table, and conversely, a record in the second table can also be related to many records in the first. In practice, this relationship does not exist directly but is achieved by linking two one-to-many relationships through an intermediary table that acts as a liaison between them.

Introducing Abies Database Software

Once Abies is opened, it presents an empty interface. To begin, you create a table, giving it a new name. When opening a new query, the cursor is positioned in the input bar, requiring you to complete all necessary fields, such as date or title.

After a table is created and populated, you can perform queries. Abies functions as a documentary database, similar to others. It is based on forms that were used in computer classes. Its environment is distinct from Microsoft Access.