資料整理——Oracle基本概念、術語（Glossary from Oracle Concepts）——第四部分
阿新 • • 發佈：2018-12-07
這些概念都是很基礎、很重要的概念。
| 概念 | 中文 | 描述 |
| data type | 資料型別 | In SQL, a fixed set of properties associated with a column value or constant. Examples include VARCHAR2 and NUMBER. Oracle Database treats values of different data types differently. |
| data warehouse | 資料倉庫 |
A relational database designed for query and analysis rather than for OLTP. |
| database access control | 資料庫訪問控制 | Restricting data access and database activities. For example, the restriction of users from querying specified tables or executing specified database statements. |
| database application | 資料庫應用程式 | A software program that interacts with a database to access and manipulate data. |
| database authentication | 資料庫身份認證 | The process by which a user presents credentials to the database, which verifies the credentials and allows access to the database. |
| database block size | 資料塊大小 | The data block size for a database set when it is created. The size is set for the SYSTEM and SYSAUX tablespaces and is the default for all other tablespaces. The database block size cannot be changed except by re-creating the database. |
| database buffer cache | 資料庫快取記憶體 | The portion of the system global area (SGA) that holds copies of data blocks. All client processes concurrently connected to the database instance share access to the buffer cache. |
| database character set | 資料庫字符集 | A character encoding scheme that determines which languages can be represented in a database. |
| database consolidation | 資料庫整合 | The general process of moving data from one or more non-CDBs into a multitenant container database (CDB). |
| database driver | 資料庫驅動程式 | Software that sits between an application and an Oracle database. The driver translates the API calls made by the application into commands that the database can process. By using an ODBC driver, an application can access any data source, including data stored in spreadsheets. The ODBC driver performs all mappings between the ODBC standard and the database. |
| database instance | 資料庫例項 | The combination of the system global area (SGA) and background processes. An instance is associated with one and only one database. In an Oracle Real Application Clusters configuration, multiple instances access a single database. |
| database link | 資料庫連結 | A schema object in one database that enables users to access objects in a different database. |
| DBMS (database management system) | 資料庫管理系統 | Software that controls the storage, organization, and retrieval of data. |
| database object | 資料庫物件 | An object in the database that can be manipulated with SQL. Schema objects such as tables and indexes reside in schemas. Nonschema objects such as directories and roles do not reside in schemas. |
| database operation | 資料庫操作 | In the context of database monitoring, a logical entity that includes a SQL statement, a PL/SQL block, or a composite of the two. |
| database point-in-time recovery | 資料庫時間點恢復 | A type of media recovery that results in a noncurrent version of the database. In this case, you do not apply all of the redo generated after the restored backup. |
| database security | 資料庫安全 | The aspect of database administration that involves user authentication, encryption, access control, and monitoring. |
| database server | 資料庫伺服器 | A server that reliably manages a large amount of data in a multiuser environment so that users can concurrently access the same data. A database server also prevents unauthorized access and provides efficient solutions for failure recovery. |
| Database Server Grid | 資料庫伺服器網格 | A collection of commodity servers connected together to run on one or more databases. |
| Database Storage Grid | 資料庫儲存網格 | A collection of low-cost modular storage arrays combined together and accessed by the computers in the Database Server Grid. |
| database service | 資料庫服務 | A named representation of one or more database instances. The service name for an Oracle database is normally its global database name. Clients use the service name to connect to one or more database instances. |
| database user | 資料庫使用者 | An account through which you can log in to an Oracle database. |
| database writer (DBW) | 資料庫寫入程式（DBW） | A background process that writes buffers in the database buffer cache to data files. |
| DDL (Data definition language) | 資料定義語言 | Includes statements such as CREATE TABLE or ALTER INDEX that define or change a data structure. |
| deadlock | 死鎖 | A situation in which two or more users are waiting for data locked by each other. Such deadlocks are rare in Oracle Database. |
| declarative language | 宣告性語言 | A nonprocedural language that describes what should be done, now how to do it. SQL and Prolog are examples of declarative languages. SQL is declarative in the sense that users specify the result that they want, not how to derive it. |
| dedicated server | 專用伺服器 | A database configuration in which a server process handles requests for a single client process. See also shared server. |
| deferrable constraint | 可延遲約束 | A constraint that permits a SET CONSTRAINT statement to defer constraint checking until a COMMIT statement is issued. A deferrable constraint enables you to disable the constraint temporarily while making changes that might violate the constraint. |
| definer's rights PL/SQL procedure | 定義者許可權PL/SQL過程 | A procedure that executes with the privileges of its owner, not its current user. |
| degree of parallelism | 並行度 | The number of parallel execution servers associated with a single operation. Parallel execution is designed to effectively use multiple CPUs. Oracle Database parallel execution framework enables you to either explicitly choose a specific degree of parallelism or to rely on Oracle Database to automatically control it. |
| dependent object | 依賴物件 | In a schema object dependency, the object whose definition references another object. For example, if the definition of object A references object B, then A is a dependent object on B. |
| descending index | 降序索引 | An index in which data is stored on a specified column or columns in descending order. |
| dimension | 維度 | A structure that categorizes data to enable users to answer business questions. Commonly used dimensions are customers, products, and time. |
| dimension table | 維度表 | A relational table that stores all or part of the values for a dimension in a star or snowflake schema. Dimension tables typically contain columns for the dimension keys, levels, and attributes. |
| directory object | 目錄物件 | A database object that specifies an alias for a directory on the server file system where external binary file LOBs (BFILEs) and external table data are located. All directory objects are created in a single namespace and are not owned by an individual schema. |
| direct path INSERT | 直接路徑插入 | An INSERT in which the database writes data directly to the data files, bypassing the database buffer cache. The database appends the inserted data to the existing data in the table. |
| direct path read | 直接路徑讀 | A single or multiblock read into the PGA, bypassing the SGA. |
| dirty read | 髒讀（Oracle資料庫不允許髒讀） | The situation that occurs when a transaction reads uncommitted data written by another transaction. Oracle Database never permits dirty reads. |
| dispatcher | 排程程式（dispatcher） | See dispatcher process (Dnnn). |
| dispatcher process (Dnnn) | 排程程式程序(Dnnn) | Optional background process present only when a shared server configuration is used. Each dispatcher process is responsible for routing requests from connected client processes to available shared server processes and returning the responses. |