Databases

• Database


  A structured collection of data that is organised and stored electronically, allowing for easy retrieval, manipulation, and management of data
• Paper-based database


  A manual system of storing data where information is recorded on physical documents like papers or files, often organised in folders or cabinets
• Electronic-based database


  A digital database that stores data in an electronic format within a computer system, allowing for efficient storage, retrieval, and processing of data
• Data types


  • Text
  • Numeric
  • Date/Time
  • Currency
  • Boolean
• Autonumber


  A data type in databases like Microsoft Access that automatically generates a unique number when a new record is added to a table, commonly used for primary key fields
• Text data type


  Stores alphanumeric characters and strings of text, such as names, descriptions, or addresses
• Numeric data type


  Includes fields that store numerical values, such as integers or decimal numbers
• Currency data type


  Used for fields that store monetary values, ensuring accurate storage and formatting for currency data
• Date/Time data type


  Stores date and time values, allowing for calculations and formatting related to dates and times
• Boolean data type


  Represents true/false or yes/no values in a database, useful for storing binary data
• Data validation


  The process of ensuring that data entered into a database meets certain criteria or rules, helping to maintain data integrity
• Data type check


  A validation process in databases that ensures that data entered into a field matches the defined data type for that field
• Range check


  A form of data validation that ensures values entered a field fall within a specified range of values
• Presence check


  Verifies whether a field or data element contains a value or is not left blank
• Simple queries


  Basic requests for specific information or data retrieval based on specified criteria
• Flat file database


  A simple database system where data is stored in a single table or file without the use of related tables
• Relational database


  Organises data into multiple tables related to each other through common fields, allowing for efficient storage and retrieval of data
• Redundant data


  The storage of duplicated data within a database, which can lead to inefficiencies and data integrity issues
• Typographical errors


  Mistakes made during data entry, such as misspellings or incorrect keystrokes
• Primary key


  A unique identifier for each record in a table that ensures each record can be uniquely identified and accessed
• Foreign key


  A field in one table that links to the primary key of another table, establishing a relationship between the two tables
• Entity Relationship Diagram (ER diagram)


  A visual representation of the relationships between tables in a database, illustrating how different entities are connected
• One-to-one relationship


  A relationship where each record in one table is associated with only one record in another table
• One-to-many relationship


  A relationship where a single record in one table can be related to multiple records in another table
• Many-to-many relationship


  A relationship where multiple records in one table can be associated with multiple records in another table, often requiring a junction or linking table to manage the relationship