ITAC Test 1
Terms
undefined, object
copy deck
- flat file
- Each application is independently developed and maintained; Integration is accomplished by passing data from one application to another: PRO: independent control & inexpensive, CON: redundant (^cost and ineficiencies), narrow focus high aggregation, difficult to integrate across applications
- data redundancy
- increases costs and inconsistencies⬦ multiple areas for same data
- database management system (DBMS)
- the middleman between the physical storage of the data seen by the user. It is the “engine†responsible for the managing the storage and retrieval of data.
- hierarchical tree model
- can support 1:1 or 1:m relationships; one directional path; linking through physical pointers (to the next related record)
- network model
- can support 1:1, 1:m, and m:n relationships; linking is explicit through physical pointers, difficult for complex entities.
- relational model
- can support 1:1, 1:m, and m:n relationships; linking is implicit through use of key fields
- data definition language (DDL)
- used to create tables and relationships among tables
- data manipulation language (DML)
- used to add delete and update data (forms are often used to facilitate this process)
- data query language (DQL)
- used to extract data from the database
- structured query language (SQL)
- a code based technique for extracting data
- query by example (QBE)
- a graphic technique for specifying selection criteria
- data dictionary
- centralized listing of all data elements in the database; includes a description of the data item the data type which applications can insert, update, or delete the data item, which reports contain the data item etc⬦
- attribute
- (same as field) parts making up the table
- field
- (same as attribute) parts making up the table
- record
- (same as tuple) data in stored in the field
- tuple
- (same as record) data in stored in the field
- cardinality
- Cardinalities are established for both sides of a relationship; The maximum cardinality from each side is taken to define the cardinality of the relationship as a whole; Optional relationships are always treated as a “many†relationship
- entity relationship (ER) diagram
- shows cardinal relationship between related entities
- event-driven modeling
- using events within major business processes to model a diagram
- operating events/processes
- only kind of event included in database modeling processes
- information events/processes
- not included in database modeling system
- decision events/processes
- not included in database modeling system
- agents
- need to determine internal and external agents involved with the operating events/processes
- resources
- need to determine resources used to complete the operating events/processes
- repeating group
- *need to recognize that they represent violations of normal form
- transitive dependency
- *need to recognize that they represent violations of normal form
- partial dependency
- *need to recognize that they represent violations of normal form