Data Base

• Definition of a database:

  • Collection of organized data
  • Can be manual or electronic
• Advantages of databases:

  • More efficient in retrieving information
  • Easy to obtain copies
  • Smaller physical space needed
  • Efficient data analysis
  • Data can be shared
  • Independence of data from software
• Features of a database:

  • Minimal data redundancy
  • Data consistency
  • Increases efficiency
  • Increases accuracy
  • Increases validity
  • Security measures
• Electronic vs. Manual Databases:

  • Electronic databases are more efficient, accurate, credible, and easy to analyze
  • Manual databases require more space, man power, and are less efficient
• Introduction to Relational Database:

  • Record: collection of fields related to one person or object
  • Data table: collection of records
  • Relational database: collection of related tables
• Primary Key:

  • Column (or combination of columns) that uniquely identifies a record
• Composite Primary Key consists of two or more columns of a table uniquely identifying a record
• Foreign Key builds a connection between two tables
• Data duplication leads to reduced efficiency and increased possibility of errors
• Commonly used data types include Numeric (Integer, Real), Text, Currency, Date/Time, Boolean
• Database Management System (DBMS) consists of tables, queries, forms, and reports
• Primary key field should be used to maintain the identity of records in a table
• In creating a relational database, different types of relationships can exist among tables: one-to-one, one-to-many, and many-to-many
• One-to-one Relationship:

  • A row in one table is related to one row in another table
• One-to-many Relationship:

  • Each record of one table is related to several records of another table
• Many-to-many Relationship:

  • A record of one table is related to several records of another table, and vice versa
• Forms are used to enter data to a table in Database Management Systems and to display entered data
• Each input record is entered to the last column of the table through a form using the Record Navigation Bar
• Query is used to obtain necessary information from the data of related tables
• Query represents data of selected fields (columns) in each table
• Reports are used to obtain printed copies of important information received from the data of related tables
• Both tables and queries can be used to design reports
• Data redundancy refers to the same data being stored in several database tables
• Data type refers to the type of data relevant to a field in a database
• In a relational database, relationships such as one-to-one, one-to-many, and many-to-many can exist
• Forms are used to enter and display data in a database
• Query is used to obtain information from a database
• Reports are used to present data from a database
• Objects in Database Management Systems are used for various purposes
• Relationships between tables are built using foreign keys
• Data redundancy can lead to inefficiency and inconsistency in a database
• Different data types are used for different types of information in a database
• Different types of relationships like one-to-one, one-to-many, and many-to-many can exist in a relational database
• Forms, queries, and reports are essential tools for managing and presenting data in a database
• Expression Builder Dialogue Box can be used to calculate values in reports
• Sum function can be used to calculate totals in reports
• Advantages of electronic databases include efficient data management and analysis
• Characteristics of a database include data consistency and security
• Primary key uniquely identifies records in a table
• Foreign key links tables together in a database