لطفا منتظر باشید ...
D
data block
In text, ntext, and image data, a data block is the unit of data transferred all at once between an application and an instance of SQL Server 2000. The term is also applied to the units of storage for these data types. In tape backup files, the data block is the unit of physical input/ output (I/O).data connection
A collection of information required to access a specific database. The collection includes a data source name and logon information. Data connections are stored in a project and are activated when the user performs an action that requires access to the database. For example, a data connection for a SQL Server database consists of the name of the database, the location of the server on which it resides, network information used to access that server, and a user ID and password.data control language (DCL)
The subset of SQL statements used to control permissions on database objects (permissions are controlled by using the GRANT and REVOKE statements).data definition
The specification of the attributes, properties, and objects in a database.data definition language (DDL)
A language, usually part of a database management system, that is used to define all attributes and properties of a database, especially row layouts, column definitions, key columns (and sometimes keying methodology), file locations, and storage strategy.data dictionary
A set of system tables that are stored in a catalog and that include definitions of database structures and related information, such as permissions.data explosion
The exponential growth in size of a multidimensional structure, such as a cube, due to the storage of aggregated data. See also sparsity.
data file
In bulk copy operations, the file that transfers data from the bulk copy OUT operation to the bulk copy IN operation. In SQL Server 2000 databases, data files hold the data stored in the database. Every SQL Server 2000 database has at least one primary data file and can optionally have multiple secondary data files to hold data that does not fit on the primary data file. See also log file.data integrity
A state in which all the data values stored in the database are correct. If incorrect data values have been stored in a database, the database is said to have lost data integrity.data lineage
Information used by Data Transformation Services (DTS), in conjunction with Meta Data Services, that records the history of package execution and data transformations for each piece of data.data manipulation language (DML)
The subset of SQL statements used to retrieve and manipulate data.data mart
A subset of the contents of a data warehouse. A data mart tends to contain data focused at the department level or on a specific business area. See also data warehouse.data member
A child member generated for a non-leaf member in a parent-child dimension. A data member contains a value directly associated with a non-leaf member that is independent of the summary value calculated from the descendants of the member. For example, a data member can contain a manager's salary so that either individual salaries or summarized salaries can be displayed.data mining model
See mining model.data modification
An operation that adds, deletes, or changes information in a database by using Transact-SQL statements such as INSERT, DELETE, and UPDATE.data pump
An OLE DB service provider that provides the infrastructure to import, export, and transform data between heterogeneous data stores by using Data Transformation Services (DTS).data scrubbing
Part of the process of building a data warehouse out of data coming from multiple online transaction processing (OLTP) systems. The process must address errors such as incorrect spellings, conflicting spelling conventions between two systems, and conflicting data (such as having two part numbers for the same part).data source
The source of data for an object, such as a cube or a dimension. The data source is also the specification of the information necessary to access source data. The data source sometimes refers to an object of ClassType clsDataSource.data source name (DSN)
The name assigned to an ODBC data source. Applications can use DSNs to request a connection to a system ODBC data source, which specifies the computer name and (optionally) the database to which the DSN maps.data type
An attribute that specifies what type of information can be stored in a column, parameter, or variable. System-supplied data types are provided by SQL Server, and user-defined data types can also be created. See also base data type.data warehouse
A database specifically structured for query and analysis. A data warehouse typically contains data representing the business history of an organization. See also fact table.data-definition query
A SQL query that contains data definition language (DDL) statements. These are statements that allow you to create or alter objects (such as tables, indexes, views, and so on) in the database and to migrate database objects from Microsoft Access.database
A collection of information, tables, and other objects organized and presented to serve a specific purpose, such as searching, sorting, and recombining data. Databases are stored in files.database catalog
The part of a database that contains the definition of all the objects in the database as well as the definition of the database. See also system catalog.
database diagram
A graphical representation of the objects in a database. A database diagram can be either a whole or partial picture of the structure of a database. This diagram includes objects for tables, the columns they contain, and the relationship between them.database file
One of the physical files that make up a database.database language
The language used for accessing, querying, updating, and managing data in relational database systems. SQL is a widely used database language. The Microsoft SQL Server implementation of SQL is called Transact-SQL.database object
A database component, such as a table, index, trigger, view, key, constraint, default, rule, user-defined data type, or stored procedure. The term database object can also refer to a database.database owner
A member of the database administrator role of a database. There is only one database owner. The owner has full permissions in that database and determines the access and capabilities provided to other users.database project
A collection of one or more data connections (a database and the information needed to access that database). When you create a database project, you can connect to one or more databases through ODBC and view their components through a visual user interface that includes Database Designer for designing and creating databases and Query Designer for creating SQL statements for any ODBC-compliant database.database role
A collection of users and groups that have the same access to an Analysis Services database. You can assign a database role to multiple cubes in the database, thereby granting the role's users access to these cubes. See also cube role, custom rule.database schema
The names of tables, fields, data types, and primary and foreign keys of a database; also known as the database structure.database script
A collection of statements used to create database objects. Transact-SQL scripts are saved as files that usually end with .SQL.dataset
In OLE DB for OLAP, the set of multi- dimensional data that is the result of executing a multidimensional expressions (MDX) SELECT statement.datetime data type
A SQL Server system data type that stores a combined date and time value from January 1, 1753 through December 31, 9999 with an accuracy of three-hundredths of a second (or 3.33 milliseconds).DBCS
See double-byte character set (DBCS).DCL
See data control language (DCL).DDL
See data definition language (DDL).deadlock
A situation where two users, each having a lock on one piece of data, attempt to acquire a lock on the other's piece. Each user would wait indefinitely for the other to release the lock unless one of the user processes is terminated. SQL Server detects deadlocks and terminates one user's process. See also livelock.decimal data type
Fixed-precision and scale- numeric data from 10^38 1 through 10^38 1.decision support
Systems designed to support the complex analysis required to discover business trends. The information retrieved from these systems allows managers to make business decisions based on a timely and accurate analysis of business trends.decision tree
A treelike model of data that is produced by certain data mining methods. Decision trees can be used for prediction. See also prediction.
declarative referential integrity (DRI)
A type of data integrity enforced by FOREIGN KEY constraints. The constraints are defined as part of a table definition that enforces proper relationships between tables. The constraints ensure that proper actions are taken when DELETE, INSERT, and UPDATE statements remove, add, or modify primary or foreign key values. The DRI actions enforced by FOREIGN_KEY constraints can be supplemented with additional referential integrity logic defined in triggers on a table.default
A data value, option setting, collation, or name assigned automatically by the system if a user does not specify the value, setting, collation, or name. A default can also refer to an action taken automatically at certain events if a user has not specified the action to take.DEFAULT constraint
A property defined for a table column that specifies a constant to be used as the default value for the column. If any subsequent INSERT or UPDATE statement specifies a value of NULL for the column or does not specify a value for the column, the constant value defined in the DEFAULT constraint is placed in the column.default database
The database to which the user is immediately connected after logging in to SQL Server.default instance
The copy of SQL Server that uses the computer name on which it is installed as its name. See also named instance, multiple instances.default language
The language that SQL Server 2000 uses for errors and messages if a user does not specify a language. Each SQL Server 2000 login has a default language.default member
The dimension member used in a query when no member is specified for the dimension. The default member of a dimension is the All member if an (All) level exists (or else an arbitrary member of the highest level). You can also set default members for individual roles in custom rules for dimension security.default result set
The default mode that SQL Server uses to return a result set back to a client. Rows are sent to the client in the order that they are placed in the result set, and the application must process the rows in this order. After executing a SQL statement on a connection, the application cannot do anything on the connection other than retrieve the rows in the result set until all the rows have been retrieved. The only other action that an application can perform before the end of the result set is to cancel the remainder of the result set. This is the fastest method to get rows from SQL Server to the client. See also firehose cursor.Delete query
A query (SQL statement) that removes rows from one or more tables.delimiter
In Transact-SQL, characters that indicate the start and end of an object name by using either double quotation marks (' ') or brackets ([ ]).denormalize
To introduce redundancy into a table in order to incorporate data from a related table. The related table can then be eliminated. Denormalization can improve efficiency and performance by reducing complexity in a data warehouse schema. See also star schema.density
The percentage of cells that contain data in a multidimensional structure. Analysis Services stores only cells that contain data. A dense cube requires more storage than a sparse cube of identical structure design. See also sparsity.deny
Removes a permission from a user account and prevents the account from gaining permission through membership in groups or roles within the permission.dependencies
The views and procedures that depend on the specified table or view.destination object
An object in a repository that participates in a relationship such that the object is the destination of the relationship. For example, the component is the destination object in the relationship project. See also origin object.
dictionary entry
Defined words in the English Query dictionary. You can make additions to the dictionary through the English Query domain editor by specifying the word, its part of speech, and an optional, irregular form.differential database backup
A database backup that records only those changes made to the database since the last full database backup. A differential backup is smaller and faster to restore than a full backup and has a minimal effect on performance.dimension
A structural attribute of a cube, which is an organized hierarchy of categories (levels) that describe data in the fact table. These categories typically describe a similar set of members upon which the user wants to base an analysis. For example, a geography dimension might include levels for Country, Region, State or Province, and City. See also level, measure, member group, virtual dimension.dimension hierarchy
One of the hierarchies of a dimension. See also hierarchy.dimension table
A table in a data warehouse whose entries describe data in a fact table. Dimension tables contain the data from which dimensions are created. See also fact table, primary dimension table.direct connect
The state of being connected to a back-end database so that any changes that you make to a database diagram automatically update your database when you save the diagram or selected items in it.direct response mode
The default mode in which SQL Server statistics are gathered separately from the SQL Server Statistics display. Data is available immediately to SQL Server Performance Monitor; however, the statistics displayed are one period behind the statistics retrieved.dirty pages
Buffer pages that contain modifications that have not been written to disk.dirty read
Reads that contain uncommitted data. For example, transaction1 changes a row. Transaction2 reads the changed row before transaction1 commits the change. If transaction1 rolls back the change, transaction2 has read a row that never logically existed.distribute
To move transactions or snapshots of data from the Publisher to Subscribers, where they are applied to the destination tables in the subscription databases.distributed query
A single query that accesses data from multiple data sources.distribution database
A database on the Distributor that stores data for replication, including transactions, snapshot jobs, synchronization status, and replication history information.distribution retention period
The distribution retention period determines the amount of information stored for a replication agent and the length of time that subscriptions will remain active in the distribution database. When the distribution retention period is exceeded, the Distribution Clean Up Agent runs.distributed transaction
A single transaction that accesses data from multiple data sources. Distributed transactions are managed by the Microsoft Distributed Transaction Coordinator (MS DTC) process and allow the four characteristics of transactions to be adhered to across disparate data sources.Distributor
A server that hosts the distribution database and stores history data, transactions, and metadata. See also local Distributor, remote Distributor.DML
See data manipulation language (DML).domain
In Windows 2000 security, a collection of computers grouped for viewing and administrative purposes that share a common security database. In relational databases, a domain refers to the set of valid values allowed in a column.
domain integrity
An integrity mechanism that enforces the validity of entries for a given column. The mechanism, such as the CHECK constraint, can restrict the possible data values by data type, format, or range of values allowed.double-byte character set (DBCS)
A character set that generally uses two bytes to represent a character, allowing more than 256 characters to be represented. DBCSs are typically used in environments that use ideographic writing systems, such as Japanese, Korean, and Chinese.DRI
See declarative referential integrity (DRI).drill down/drill up
A technique for navigating through levels of data ranging from the most summarized (up) to the most detailed (down). For example, when viewing the details of sales data by year, a user can drill down to display sales data by quarter (and furthermore, to display data by month).drill through
To retrieve the detailed data from which the data in a cube cell was summarized.DSN
See data source name (DSN).DSN-less connection
A type of data connection that is created based on information in a data source name (DSN) but that is stored as part of a project or application. DSN-less connections are especially useful for Web applications because they enable you to move the application from one server to another without recreating the DSN on the new server.DTS package
An organized collection of connections, Data Transformation Services (DTS) tasks, DTS transformations, and workflow constraints defined by the DTS object model and assembled either with a DTS tool or programmatically.DTS package template
A model Data Transformation Services (DTS) package. The template is used to help create and configure a particular type of package.dump
See backup.dump file
See backup file.dynamic cursor
A cursor that can reflect data modifications made to the underlying data while the cursor is open. Updates, deletes, and inserts made by users are reflected in the dynamic cursor.dynamic filter
Merge replication filters that restrict data based on a system function or a user-defined function, such as SUSER_SNAME().dynamic locking
The process that SQL Server uses to determine the most cost-effective locks to use at any one time.dynamic recovery
The process that detects and/or attempts to correct software failure or loss of data integrity within a relational database management system (RDBMS).dynamic snapshot
A snapshot of a merge publication with dynamic filters that is applied by using bulk copy files to improve performance.dynamic SQL statements
In Embedded SQL for C, a SQL statement built and executed at run time.
