WGU C170 Chapter 5 correctly answered 2022

WGU C170 Chapter 5 correctly answered 2022access plan A set of instructions generated at application compilation time that is created and managed by a DBMS. The access plan predetermines how an application's query will access the database at run time. algorithms A process or set of operations in a calculation. automatic query optimization A method by which a DBMS finds the most efficient access path for the execution of a query. B-tree index An ordered data structure organized as an upside-down tree. bitmap index An index that uses a bit array (0s and 1s) to represent the existence of a value or condition. buffer cache See data cache data cache A shared, reserved memory area that stores the most recently accessed data blocks in RAM. Also called buffer cache. data files A named physical storage space that stores a database's data. It can reside in a different directory on a hard disk or on one or more hard disks. All data in a database is stored in data files. A typical enterprise database is normally composed of several data files. A data file can contain rows from one or more tables. data sparsity A column distribution of values or the number of different values a column can have. database performance tuning A set of activities and procedures designed to reduce the response time of a database system—that is, to ensure that an end-user query is processed by the DBMS in the minimum amount of time. database statistics In query optimization, measurements about database objects, such as the number of rows in a table, number of disk blocks used, maximum and average row length, number of columns in each row, and number of distinct values in each column. Such statistics provide a snapshot of database characteristics. DBMS performance tuning Activities to ensure that clients' requests are addressed as quickly as possible while making optimum use of existing resources. dynamic query optimization The process of determining the SQL access strategy at run time, using the most up-to-date information about the database extents In a DBMS environment, refers to the ability of data files to expand in size automatically using predefined increments. file group See table space. hash index An index based on an ordered list of hash values. input/output (I/O) request A low-level data access operation that reads or writes data to and from computer devices. manual query optimization An operation mode that requires the end user or programmer to define the access path for the execution of a query. manual statistical generation mode A mode of generating statistical data access information for query optimization. In this mode, the DBA must periodically run a routine to generate the data access statistics—for example, running the RUNSTAT command in an IBM DB2 database. procedure cache See SQL cache.