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43 Cards in this Set
- Front
- Back
Traditional file approach
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no mechanism for tagging, retrieving, or manipulating data; nconvenient: Program-data, dependency, High data redundancy, Low data integrity
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Database approach
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provides powerful mechanism for managing and manipulating data; data organized as entities
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Data redundancy
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duplication of data
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Data integrity
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accuracy of data
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Entity
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an object about which an organization chooses to collect data, such as: People, Events, Products
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Character
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smallest piece of data; A single letter or a digit
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Field
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single piece of information about entity; hold images, sounds, video clips, etc.
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Record
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collection of related fields
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File
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collection of related records
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Database management system (DBMS)
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program used to: Build databases, Populate a database with data, Manipulate data in a database
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Query
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a message to the database requesting data from specific records and/or fields
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Database administrator (DBA)
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the person responsible for managing the database; Sets user limits for access to data in the database
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Database model
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general logical structure; How records stored in the database; How relationships between records are established
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Relational Model
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consists of tables
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Tuple
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record (or row)
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Attribute
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field (or column)
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Relation
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table of records
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Key
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a field whose values identify records; Used to retrieve records
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Primary key
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a field by which records are uniquely identified; Each record in the table must have a unique key value
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Composite key
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combination of fields that serve as a primary key
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Foreign key
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a field that is common to two tables; Used to link the tables; This field is a primary key in one table and a foreign key in the other
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Object-oriented database model
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uses object-oriented approach for the database structure
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Join table
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composite of tables
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One-to-many relationship
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one item in a table is linked to many items in the other table
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Many-to-many relationship
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many items in a table are linked to many items of the other table
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Encapsulation
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combined storage of data and relevant procedures to process it; Allows object to be “planted” in different data sets
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Inheritance
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the ability to create a new object by replicating the characteristics of an existing (parent) object
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Object-oriented databases (ODBs)
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store data objects, not records
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Relational operation
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creates a temporary subset of a table or tables; create a limited list or a joined table list
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Select
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a selection of records based on conditions
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Project
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a selection of certain columns from a table
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Join
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join data from multiple tables to create a temporary table
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Structured Query Language (SQL)
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query language of choice for DBMSs; Advantages of SQL: It is an international standard; It is provided with most relational DBMSs; It has easy-to-remember, intuitive commands
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Schema:
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a plan that describes the structure of the database, including: Names and sizes of fields; Identification of primary keys; Relationships
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Data dictionary
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a repository of information about the data and its organization; Also called metadata
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metadata
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the data about the data; including - Source of the data; Tables related to the data; Field and index information; Programs and processes that use the data; Population rules: what is inserted, or updated, and how often
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Data modeling
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analysis of an organization’s data and identification of the data relationships; A proactive process; Develops a conceptual blueprint of the database
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Entity relationship diagram
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a graphical representation of all entity relationships; made of - Boxes: identify entities; Lines: indicate relationship between entities; Crossbars: indicate mandatory fields; Circles: indicate optional; Crow’s feet: identify “many”
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Data warehouse
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a large repository database that supports management decision making; Typically relational; Data is collected from transactional databases
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Data mart:
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a smaller collection of data focusing on a particular subject or department
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Extraction phase
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create files from transactional database
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Transformation phase
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cleanse and modify the data format
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Loading phase
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transfer files to data warehouse
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