Transcript Chapter 14

Chapter 14
Database Management Systems:
Getting Data Together
database programs store information so
that users can quickly locate, organize,
and display information
databases are found on all sizes and
types of computers
Basic database components
field - a group of related characters
record - a group of related fields
file (table) - a group of related records
database - one or more related files
Characteristics of a good
data integrity - data is valid
data independence - data can be used by other
data security
– only authorized individuals can access and/or
change data
– data should be protected against loss or damage
data maintenance - procedures exist for adding,
deleting, and updating records
avoid data redundancy - data should not be
unnecessarily repeated
Typical database features
creation of a database
– user must specify the name and type of each field
to define the basic record structure
entering data
– includes adding, deleting, and modifying records
browse data - examine contents of files
query the database - extract specific data
organize - sort data based on user needs
generate reports
– determine content
– design layout
Database Models
hierarchical, network, relational, object-oriented
relational model
– most flexible and easily understood
– most common model for PC databases
– database file is envisioned as a two-dimensional
• rows correspond to records
• columns correspond to fields
– may include several files
• data in files is linked by a key field
• key field - the contents of this field uniquely
identify a record
Object-oriented DBMS
developed to store many types of data
– graphics, video, audio, etc.
examples include
– medical record databases
– Geographical Information Systems (GIS)
– educational instruction systems
Data Warehousing
data warehouse - a collection of data
that has been captured from a
database, on a scheduled basis, over a
scheduled period of time
data mining - use of statistical and
artificial intelligence techniques to
discover patterns, relationships, and
trends in data