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BEC 41
Information Technology
Term | Definition |
---|---|
Systems development lifecycle (SDLC) | 1)planning 2) analysis3) design, 4)development 5)implementation, 6)maintenance |
CPU | contains an arithmetic/logic unit- performs mathematical and logical comparisons, primary memory ( Random Access M, Read Only M) , control unit – interprets program instructions and coordinates input, output, and storage devices. |
Storage devices ( ones I don’t know) | RAID- redundant array of independent disks- storing same data on multiple magnetic discs; SSD ( Solid State Drives) – use microchips to store data ( thumb drives, USB drives); Cloud Based Storage ( aka Storage as a Service SaaS) |
Buffer | a temporary storage unit used to hold data during computer operations |
Batch processing | transactions flow through the system in groups of like transactions |
Online real time processing | (aka: direct access processing) transactions are processed in order in which they occur; files and programs are stored online so that updating can take place as the edited data flows to the application. restricted access to authorized persons. |
OLTP: online transaction processing | databases that support daily operations |
OLAP: online analytical systems | software that enables the user to query a system and conduct an analysis while the user is at a PC. Used primarily for analytical analysis; used as decision support systems and is periodically downloaded to a data warehouse or data mart |
Artificial intelligence (AI) | software designed to help humans make decisions and solve problems. Expert system: allows decisions comparable to that of an expert- the expert knowledge is modeled in to a mathematical system |
Bit | a binary digit ( 0 or 1) which is the smallest storage unit in a computer |
Byte | a groups of adjacent bits ( usually 8) that is treated as a single unit, or character by the computer. |
Field | a group of related characters |
Record | an ordered set of logically related fields. |
File | a group of related records |
Table | a groups of related records in a relational database with a unique identifier ( primary key field) in each record |
Database | a group of related files or a group of related tables |
Array | an aggregate that consists of data objects with attributes, each of which may be uniquely referenced by an index( address) |
Master file | a file containing relatively permanent information and used as a source reference and periodically updated with a detail( transaction) file |
Database normalization | the process of separating the database into logical tables to avoid certain kinds of updating ad anomalies |
Foreign key | the fields that are common to two or more related tables in a relational database |
REA data model | a data model designed for use in designing accounting information databases. Resources- identifiable objects that have economic value; Events- business activities; Agents- people or organizations about which the data is collected |
Meta- data | definitional data that provides information about or documentation of other data managed within the application or environment. |
Data dictionary ( aka: data repository or data directory) | a data structure that stores meta- data |
Structured query language ( SQL) | the most common language used in creating and querying relational databases. 3 types of commands: DDL ( data defined language) ; DML ( data manipulation language); DCL ( data control language) |
Hierarchical data structure | the data elements at one level “own” the data elements at the end lower level |
Networked data structure | each data element can have several owners and can own several other elements |
Relational data structure | a groups of related spreadsheets; each row = a record, each column = a field |
Object oriented structure | attributes and methods are include in structures called object classes. |
Distributed data structure | a single database that is spread physically across computers in multiple locations that are connected by a da data communication link. Usually relational, object- oriented, or object- relational |
User department controls | strict controls over who is authorized to read or change the database |
Access controls | controls within a database that limit user to reading and/or changing only authorized portions of the database |
Restricting privileges | limits access of users to a database and also and operations a user may perform |
Logical views | authorized views of only portions of a database for which they have a valid need |
Back up database and log of transactions | DB backed up several time per week, generally to magnetic tape. Log of transactions is maintained. Recovery method used to restore the DB and log of transactions used to update DB up to the point of failure. |
Backup facility | maintained with an external vendor who will process data in the event of an emergency |
Advantages of a database system | 1) data independence 2) minimal data redundancy 3) data sharing 4) reduced program maintenance 4) commercial applications can be modified to fit company needs |
Disadvantages of a database system | 1) specialized personnel with database expertise 2) installation is costly 2) conversion of traditional file systems costly 3) comprehensive backup and recovery procedures are necessary |
Database replication | replicate the database in one or more locations- thus all data is recorded to replicated databases.% |
Controls to detect and prevent equipment failure | parity check-a special bit is added to each character 2) echo check-for data transmission- receiving repeats back to sender and resends any characters received incorrectly 3) boundary protection control’s, 4) periodic mtce 5) diagnostic routines. |