Download WGU D072 Exam Study Guide and more Exams Database Management Systems (DBMS) in PDF only on Docsity!
Data Management – Foundations WGU -
C175. Questions and answers, 100%
Accurate. Graded A+
3 V's of Big Data - ✔✔-Three basic characteristics of Big Data databases: volume, velocity, and variety. Abstract Data Type (ADT) - ✔✔-Data type that describes a set of similar objects with shared and encapsulated data representation and methods. An abstract data type is generally used to describe complex objects. See also class. ad hoc query - ✔✔-A "spur-of-the-moment" question. alias - ✔✔-An alternative name for a column or table in a SQL statement. ALTER TABLE - ✔✔-The SQL command used to make changes to table structure. When the command is followed by a keyword (ADD or MODIFY), it adds a column or changes column characteristics. American National Standards Institute (ANSI) - ✔✔-The group that accepted the DBTG recommendations and augmented database standards in 1975 through its SPARC committee.
analytical database - ✔✔-A database focused primarily on storing historical data and business metrics used for tactical or strategic decision making. AND - ✔✔-The SQL logical operator used to link multiple conditional expressions in a WHERE or HAVING clause. It requires that all conditional expressions evaluate to true. application programming interface (API) - ✔✔-Software through which programmers interact with middleware. An API allows the use of generic SQL code, thereby allowing client processes to be database server-independent. atomic attribute - ✔✔-An attribute that cannot be further subdivided to produce meaningful components. For example, a person's last name attribute cannot be meaningfully subdivided. atomicity - ✔✔-The transaction property that requires all parts of a transaction to be treated as a single, indivisible, logical unit of work. All parts of a transaction must be completed or the entire transaction is aborted. attribute - ✔✔-A characteristic of an entity or object. An attribute has a name and a data type.
Boyce-Codd normal form (BCNF) - ✔✔-A special type of third normal form (3NF) in which every determinant is a candidate key. A table in BCNF must be in 3NF. See also determinant. Business intelligence (BI) - ✔✔-A comprehensive, cohesive, and integrated set of tools and processes used to capture, collect, integrate, store, and analyze data with the purpose of generating and presenting information to support business decision making. business rule - ✔✔-A description of a policy, procedure, or principle within an organization. For example, a pilot cannot be on duty for more than 10 hours during a 24-hour period, or a professor may teach up to four classes during a semester. candidate key - ✔✔-A minimal superkey; that is, a key that does not contain a subset of attributes that is itself a superkey. See key. cardinality - ✔✔-A property that assigns a specific value to connectivity and expresses the range of allowed entity occurrences associated with a single occurrence of the related entity. cascading order sequence - ✔✔-A nested ordering sequence for a set of rows, such as a list in which all last names are alphabetically ordered and, within the last names, all first names are ordered.
class - ✔✔-A collection of similar objects with shared structure (attributes) and behavior (methods). A class encapsulates an object's data representation and a method's implementation. Classes are organized in a class hierarchy. class diagram notation - ✔✔-The set of symbols used in the creation of class diagrams in UML object modeling. class diagrams - ✔✔-A diagram used to represent data and their relationships in UML object notation. class hierarchy - ✔✔-The organization of classes in a hierarchical tree in which each parent class is a superclass and each child class is a subclass. See also inheritance. client - ✔✔-Any process that requests specific services from server processes in a client/server environment. client node - ✔✔-One of three types of nodes used in the Hadoop Distributed File System (HDFS). The client node acts as the interface between the user application and the HDFS. See also name node and data node.
conceptual model - ✔✔-The output of the conceptual design process. The conceptual model provides a global view of an entire database and describes the main data objects, avoiding details. conceptual schema - ✔✔-A representation of the conceptual model, usually expressed graphically. See also conceptual model. connectivity - ✔✔-The type of relationship between entities. Classifications include 1:1, 1:M, and M:N. constraint - ✔✔-A restriction placed on data, usually expressed in the form of rules. For example, "A student's GPA must be between 0.00 and 4.00." Constraints are important because they help to ensure data integrity. COUNT - ✔✔-A SQL aggregate function that outputs the number of rows containing not null values for a given column or expression, sometimes used in conjunction with the DISTINCT clause. CREATE INDEX - ✔✔-A SQL command that creates indexes on the basis of a selected attribute or attributes. CREATE TABLE - ✔✔-A SQL command that creates a table's structures using the characteristics and attributes given.
Crow's Foot notation - ✔✔-A representation of the entity relationship diagram that uses a three-pronged symbol to represent the "many" sides of the relationship. cube cache - ✔✔-In multidimensional OLAP, the shared, reserved memory area where data cubes are held. Using the cube cache assists in speeding up data access. dashboards - ✔✔-In business intelligence, a web-based system that presents key business performance indicators or information in a single, integrated view with clear and concise graphics. data - ✔✔-Raw facts, or facts that have not yet been processed to reveal their meaning to the end user. data anomaly - ✔✔-A data abnormality in which inconsistent changes have been made to a database. For example, an employee moves, but the address change is not corrected in all files in the database. data cube - ✔✔-The multidimensional data structure used to store and manipulate data in a multidimensional DBMS. The location of each data value in the data cube is based on its x-, y-, and z- axes. Data cubes are static, meaning they must be created before they are used, so they cannot be created by an ad hoc query.
data management - ✔✔-A process that focuses on data collection, storage, and retrieval. Common data management functions include addition, deletion, modification, and listing. data manipulation language (DML) - ✔✔-The set of commands that allows an end user to manipulate the data in the database, such as SELECT, INSERT, UPDATE, DELETE, COMMIT, and ROLLBACK. data mart - ✔✔-A small, single-subject data warehouse subset that provides decision support to a small group of people. data model - ✔✔-A representation, usually graphic, of a complex "real-world" data structure. Data models are used in the database design phase of the Database Life Cycle. data modeling - ✔✔-The process of creating a specific data model for a determined problem domain. data node - ✔✔-One of three types of nodes used in the Hadoop Distributed File System (HDFS). The data node stores fixed-size data blocks (that could be replicated to other data nodes). See also client node and name node. data processing (DP) specialist - ✔✔-The person responsible for developing and managing a computerized file processing system.
data redundancy - ✔✔-Exists when the same data is stored unnecessarily at different places. data visualization - ✔✔-Abstracting data to provide information in a visual format that enhances the user's ability to effectively comprehend the meaning of the data. data warehouse - ✔✔-An integrated, subject-oriented, time-variant, nonvolatile collection of data in a specialized database that stores historical and aggregated data in a format that provides support for decision making. database - ✔✔-A shared, integrated computer structure that houses a collection of related data. A database contains two types of data: end-user data (raw facts) and metadata. database design - ✔✔-The process that yields the description of the database structure and determines the database components. The second phase of the Database Life Cycle. database management system (DBMS) - ✔✔-The collection of programs that manages the database structure and controls access to the data stored in the database.
desktop database - ✔✔-A single-user database that runs on a personal computer. determinant - ✔✔-Any attribute in a specific row whose value directly determines other values in that row. See also Boyce-Codd normal form (BCNF). determination - ✔✔-The role of a key. In the context of a database table, the statement "A determines B" indicates that knowing the value of attribute A means that the value of attribute B can be looked up. dimension tables - ✔✔-In a data warehouse, tables used to search, filter, or classify facts within a star schema. discipline-specific databases - ✔✔-A database that contains data focused on specific subject areas. DISTINCT - ✔✔-A SQL clause that produces only a list of values that are different from one another. domain - ✔✔-In data modeling, the construct used to organize and describe an attribute's set of possible values.
drill down - ✔✔-To decompose data into more atomic components—that is, data at lower levels of aggregation. This approach is used primarily in a decision support system to focus on specific geographic areas, business types, and so on. DROP INDEX - ✔✔-A SQL command used to delete database objects such as tables, views, indexes, and users. DROP TABLE - ✔✔-A SQL command used to delete database objects such as tables, views, indexes, and users. enterprise database - ✔✔-The overall company data representation, which provides support for present and expected future needs. entity - ✔✔-A person, place, thing, concept, or event for which data can be stored. See also attribute. entity instance - ✔✔-A row in a relational table. Also known as entity occurrence. entity integrity - ✔✔-The property of a relational table that guarantees each entity has a unique value in a primary key and that the key has no null values.
EXISTS - ✔✔-In SQL, a comparison operator that checks whether a subquery returns any rows. extended relational data model (ERDM) - ✔✔-A model that includes the object-oriented model's best features in an inherently simpler relational database structural environment. See extended entity relationship model (EERM). Extensible Markup Language (XML) - ✔✔-A meta-language used to represent and manipulate data elements. Unlike other markup languages, XML permits the manipulation of a document's data elements. XML facilitates the exchange of structured documents such as orders and invoices over the Internet. external model - ✔✔-The application programmer's view of the data environment. Given its business focus, an external model works with a data subset of the global database schema. external schema - ✔✔-The specific representation of an external view; the end user's view of the data environment. extraction, transformation, and loading (ETL) - ✔✔-In a data warehousing environment, the integrated processes of getting data from original sources into the data warehouse. ETL includes retrieving data
from original data sources (extraction), manipulating the data into an appropriate form (transformation), and storing the data in the data warehouse (loading). field - ✔✔-An alphabetic or numeric character or group of characters that defines a characteristic of a person, place, or thing. For example, a person's Social Security number, address, phone number, and bank balance all constitute fields. file - ✔✔-A named collection of related records. first normal form (1NF) - ✔✔-The first stage in the normalization process. It describes a relation depicted in tabular format, with no repeating groups and a primary key identified. All nonkey attributes in the relation are dependent on the primary key. flags - ✔✔-Special codes implemented by designers to trigger a required response, alert end users to specified conditions, or encode values. Flags may be used to prevent nulls by bringing attention to the absence of a value in a table. foreign key (FK) - ✔✔-An attribute or attributes in one table whose values must match the primary key in another table or whose values must be null. See key.
GROUP BY - ✔✔-A SQL clause used to create frequency distributions when combined with any of the aggregate functions in a SELECT statement. Hadoop - ✔✔-A Java based, open source, high speed, fault-tolerant distributed storage and computational framework. Hadoop uses low-cost hardware to create clusters of thousands of computer nodes to store and process data. Hadoop Distributed File System (HDFS) - ✔✔-A highly distributed, fault-tolerant file storage system designed to manage large amounts of data at high speeds. hardware independence - ✔✔-A condition in which a model does not depend on the hardware used in the model's implementation. Therefore, changes in the hardware will have no effect on the database design at the conceptual level. HAVING - ✔✔-A clause applied to the output of a GROUP BY operation to restrict selected rows. hierarchical model - ✔✔-An early database model whose basic concepts and characteristics formed the basis for subsequent database development. This model is based on an upside-down tree structure in
which each record is called a segment. The top record is the root segment. Each segment has a 1:M relationship to the segment directly below it. hub - ✔✔-A warehouse of data packets housed in a central location on a local area network. It contains multiple ports that copy the data in the data packets to make it accessible to selected or all segments of the network. identifiers - ✔✔-One or more attributes that uniquely identify each entity instance. IN - ✔✔-In SQL, a comparison operator used to check whether a value is among a list of specified values. index - ✔✔-An ordered array of index key values and row ID values (pointers). Indexes are generally used to speed up and facilitate data retrieval. Also known as an index key. information - ✔✔-The result of processing raw data to reveal its meaning. Information consists of transformed data and facilitates decision making. inheritance - ✔✔-In the object-oriented data model, the ability of an object to inherit the data structure and methods of the classes above it in the class hierarchy. See also class hierarchy.
