Glosario de Bases de Datos Sybase, "A,B"

Termino or Word	Description - Descripcion
access - acceso	The use of a select, insert , update, or delete command on a table or view. Se define acceso como el uso de los comandos select (seleccionar) , insert (insertar), update (actualizar) o delete (borrar o remover), sobre una tabla o una vista.
access method - metodo de acceso	The method used to find the data rows needed to satisfy a query. Access methods can be serial or parallel. Serial access methods include: table scan , nonclustered index access, clustered index access. A parallel access method is either a partition-based access method or a hash-based access method . Partition-based access methods include parallel partition scan and parallel clustered index partition scan . Hash-based access methods include parallel hash-based table scan and parallel nonclustered index hash-based scan . Es el metodo usado para encontrar los datos requeridos para producir los resultados de una consulta. Los métodos de acceso pueden ser seriales o paralelos. Los métodos de acceso serial incluyen: analisis de una tabla (table scan, nonclustered el acceso del índice, acceso arracimado del índice. Un método de acceso paralelo es un método de acceso particio'n-basado o un método de acceso picadillo-basado . los métodos de acceso Particio'n-basados incluyen la exploración paralela de la partición y son paralelo a la exploración arracimada de la partición del índice . los métodos de acceso Picadillo-basados incluyen la exploración picadillo-basada paralelo de la tabla y el paralelo nonclustered la exploración picadillo-basada índice .
Adaptive Server - Servidor Flexible	The server in the Sybase Client/Server architecture (called SQL Server prior to the Adaptive Server 11.5 release). Adaptive Server manages multiple databases and multiple users, keeps track of the actual location of data on disks, maintains mapping of logical data description to physical data storage, and maintains data and procedure caches in memory. See also segment .
Adaptive Server engine	See engine .
address lock	A type of lock applied to certain resources such as network buffers or internal structures. Address locks are also used to lock index pages.
aggregate function	A function that generates summary values that appear as new columns in the query results. The aggregate functions available in Transact-SQL are: average (avg), maximum ( max), minimum ( min ), sum (sum), and count of the number of items (count ).
alias	A pseudonym that allows an Adaptive Server user to be known in a database as another user.
allocation page	The first page of an allocation unit, which tracks the use of all pages in the allocation unit.
allocation unit	A logical unit of 1/2 MB, or 256 2K pages. The disk init command initializes a new database file for Adaptive Server and divides it into allocation units.
Application Program Interface (API)	A subroutine that allows client applications to interface with SQL Server. Also known as a library.
application-building tool	See development tool .
argument	A value supplied to a function or procedure that is required to evaluate the function.
arithmetic expression	An expression that contains only numeric operands and returns a single numeric value. In Transact-SQL, the operands can be of any Adaptive Server numeric datatype. They can be functions, variables, parameters, or they can be other arithmetic expressions. Also called a numeric expression.
arithmetic operators	Symbols that enable you to create arithmetic expression s in SQL statements. Addition (+), subtraction (-), division (/), and multiplication () can be used with numeric columns. Modulo (%) can be used with int* , smallint, and tinyint columns only. See also comparison operators .
audit trail	Audit records stored in the sybsecurity database.
auditing	The act of recording security-related system activity that can be used to detect penetration of the system and misuse of system resources.
automatic recovery	A process that runs every time Adaptive Server is restarted. The process ensures that all transactions that completed before Adaptive Server stopped are brought forward and all incomplete transactions are rolled back.
B-tree	Short for balanced tree, or binary tree. Adaptive Server uses B-tree indexing. All leaf pages in a B-tree are the same distance from the root page of the index. B-trees provide consistent and predictable performance, good sequential and random record retrieval, and a flat tree structure.
backup	A copy of a database or transaction log, used to recover from a media failure.
base date	January 1, 1900; the date supplied by Adaptive Server when a user does not specify a value for a date column.
base tables	The permanent tables on which a view is based. Also called underlying tables.
batch	One or more Transact-SQL statements terminated by an end-of-batch signal, which submits them to Adaptive Server for processing.
Boolean expression	An expression that evaluates to TRUE (1), or FALSE (0). Boolean expressions are often used in control of flow statements, such as if or while conditions.
buffer	A unit of storage in a memory pool. A single buffer cache can have pools configured for different I/O sizes, or buffer sizes. All buffers in a pool are the same size. If a pool is configured for 16K I/O, all buffers are 16K, holding eight data pages. Buffers are treated as a unit; all data pages in a buffer are read, written, or flushed from cache simultaneously.
buffer cache	An area of memory within Adaptive Server that contains the in-memory images of database pages, as well as the data structures required to manage the pages. Each cache is given a unique name that is used for configuration purposes. By default, Adaptive Server has a single cache named "default data cache." Caches configured by users are called "user defined caches." Buffer caches are also referred to as data caches and named caches.
buffer pool	An area of memory within a buffer cache that contains a set of buffers linked together on an MRU/LRU (most recently used/least recently used) list.
buffer reuse strategy	Reading pages into the data cache at the LRU end of the cache chain, so that the same buffer is available for reuse immediately. This strategy keeps select commands that require large numbers of page reads from flushing other data from the cache.
built-in functions	A wide variety of functions that take one or more arguments and return results. The built-in functions include aggregate functions , mathematical functions , system functions , string functions , text and image functions , date functions , and datatype conversion functions .
bulk copy	The process of copying data in and out of databases. In Adaptive Server this operation is performed with the bcp utility.
business rule	A rule that restricts input and updates based on real-world requirements. For example, a sales database can be required to forbid the sale of any items for which there is insufficient stock. Adaptive Server can check each row before it is added to the sales_orders table and enforce the requirement using the business rule on the quantity column.

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