Chapter 15

• cascade delete


  ensures that changes made in the linked table (where the foreign key is entered) are also shown in in the primary table
• composite key fields


  a key field which consists of two or more key fields
• cascade update


  Ensures that changes made in the linked table (where the foreign key is entered) are also shown in the primary table.
• data integrity


  the accuracy and consistency of data stored in a database
• data redundancy


  the unnecessary repetition of data in a database
• design view


  a view that allows the designer to make adjustments to the content or layout of an object created in a digital application
• input masks


  a method of controlling the format of data which is being entered into a database
• look-up list


  a list of all data that can be used to provide all available values for a given data field
• mail merge


  a word processing feature that allows users to personalise letters with names and addresses in a database
• merge fields


  field used to indicate the location in a document where data extracted from a database file should be inserted following the completion of a mail merge process
• parameter query


  A query where the user is prompted to enter search criteria each time a query is activated.
• report view


  Displays the report/form in the format which is accessible to the end user once the digital application is complete.
• expand SQL


  structured query language
• What is SQL?


  a specialised language used to create databases and to retrieve and process data in a database
• what is a database

  a collection of data that is organised so that its contents can easily be accessed managed and updated
• name the two types of databases


  flat file

  relational database
• define flatfile database


  a database structure in which all of the data is entered and stored in a single table, usually in a single large file
• define relational database


  a collection of information organised as a set of formally described tables from which required items of data can be retrieved quickly by computer programs
• relational databases reduce ...... and increase .....


  reduce data redundancy

  increase data intergrity
• since data is not repeated the amount of storage required is _____

  reduced
• 3 main features in a relational database


  table-in relational databases the data is organised into tables which are connected together by relationships

  
  

  record-the complete set of information stored for an item. Records are made up of fields, each one holds one piece of information. records are rows

  
  

  fields-a location in a record at which a particular type of data is stored. fields are columns
• name the 3 types of keys


  primary key- a field that uniquely identifies a record within table

  composite key- a primary key that includes more than one field

  foreign key- a primary key from one table is stored in another table as a non-key field
• query


  a way of searching and extracting data from a database to answer a question

  the query checks each record and produces a list of data that satisfies the query criteria

  to create a query, criteria are added to more than one field in the table
• form


  a common way to collect data from people

  a form wizard can be used to create forms for data input when developing a database

  they are used to enter new records and modify an existing record

  forms minimise human error

  when data is entered into a form it is automatically added into the specified table and stored as part of the database
• report


  allows tables and results from queries to be presented in a user friendly way

  layout can be customised making it visually attractive and easy for user to read

  grouping data in ascending and descending order is also possible
• macro


  a small program written to perform a repetitive task in a database automatically
• in order to have a relationship what needs to be present


  a common field that exists in each table
• why is it important to enforce referential integrity


  ensures deletions/updates made in the linked table
• 3 main components of SQL


  select-specify the data to be displayed (fields)

  from-identify the source of the data (table)

  where- identify the criteria to be used to select data from the source (criteria)