資料整理——Oracle基本概念、術語（Glossary from Oracle Concepts）——第三部分
阿新 • • 發佈：2018-12-07
一邊整理資料，一邊學習這些基本概念，這時間花的值。
| 概念 | 中文 | 描述 |
| commit | 提交 | Action that ends a database transaction and makes permanent all changes performed in the transaction. |
| commit cleanout | 提交清除 | The automatic removal of lock-related transaction information (ITL entry) from the blocks after a commit. The database removes the ITL entry only if modified blocks containing data from the committed transaction are still in the SGA, and if no other session is modifying them. |
| common role | 普通角色 | A role that exists in all containers in a multitenant container database (CDB). |
| common user | 普通使用者 | In a multitenant container database (CDB), a database user that exists with the same identity in every existing and future PDB. |
| complete refresh |
完整重新整理 | An execution of the query that defines a materialized view. A complete refresh occurs when you initially create the materialized view, unless the materialized view references a prebuilt table, or you define the table as BUILD DEFERRED. |
| composite database operation | 複合資料庫操作 |
Activity between two points in time in a single database session. |
| composite index | 複合索引 | An index on multiple columns in a table. |
| composite partitioning | 複合分割槽 | A partitioning strategy in which a table is partitioned by one data distribution method and then each partition is further divided into subpartitions using a second data distribution method. |
| composite unique key | 複合唯一鍵 | A set of two or more columns with a unique key constraint. |
| compound trigger | 複合觸發器 | A trigger can that can fire at multiple timing points. For example, a compound trigger might fire both before and after the triggering statement. |
| compression unit | 壓縮單元 | In Hybrid Columnar Compression, a logical construct that stores a set of rows. When you load data into a table, the database stores groups of rows in columnar format, with the values for each column stored and compressed together. After the database has compressed the column data for a set of rows, the database fits the data into the compression unit. |
| concatenated index | 連線索引（同複合索引） | See composite index. |
| condition | 條件 | The combination of one or more expressions and logical operators in a SQL statement that returns a value of TRUE, FALSE, or UNKNOWN. For example, the condition 1=1 always evaluates to TRUE. |
| conflicting write | 寫衝突 | In a read committed transaction, an situation that occurs when the transaction attempts to change a row updated by an uncommitted concurrent transaction. |
| connection | 資料庫連線 | Communication pathway between a client process and an Oracle database instance. See also session. |
| connection pooling | 連線池 | A resource utilization and user scalability feature that maximizes the number of sessions over a limited number of protocol connections to a shared server. |
| consistent backup | 一致備份 | A whole database backup that you can open with the RESETLOGS option without performing media recovery. By its nature, a consistent backup of the whole database does not require the application of redo to be made consistent. See also inconsistent backup. |
| consistent read get | 一致讀get | The retrieval of a version of a block in the database buffer cache that is consistent to a specific SCN (part of read consistency). If the database needs a block to satisfy a query, and if no block in the database buffer cache is consistent to the correct SCN, then the database attempts to obtain the correct version of the block from undo data. |
| container | 容器 | In a multitenant container database (CDB), either the root or a PDB. |
| container data object | 容器資料物件 | In a CDB, a table or view containing data pertaining to multiple containers and possibly the CDB as a whole, along with mechanisms to restrict data visible to specific common users through such objects to one or more containers. Examples of container data objects are Oracle-supplied views whose names begin with V$ and CDB_. |
| context | 資料庫上下文 | A set of application-defined attributes that validates and secures an application. The SQL statement CREATE CONTEXT creates namespaces for contexts. |
| control file | 控制檔案 | A binary file that records the physical structure of a database and contains the names and locations of redo log files, the time stamp of the database creation, the current log sequence number, checkpoint information, and so on. |
| cross-container operation | 跨容器操作 | In a CDB, a DDL statement that affects the CDB itself, multiple containers, multiple common users or roles, or a container other than the one to which the user is connected. Only a common user connected to the root can perform cross-container operations. |
| cube | 資料立方體(cube) | An organization of measures with identical dimensions and other shared characteristics. The edges of the cube contain the dimension members, whereas the body of the cube contains the data values. |
| current mode get | 獲取當前模式 | The retrieval of the version of a data block as it exists right now in the buffer cache, without using read consistency. Only one version of a block exists in current mode at any one time. |
| current online redo log file | 當前線上重做日誌檔案 | The online redo log file to which the log writer (LGWR) process is actively writing. |
| cursor | 遊標（私有SQL區名） | A handle or name for a private SQL area in the PGA. Because cursors are closely associated with private SQL areas, the terms are sometimes used interchangeably. |
| data block | 資料塊 | Smallest logical unit of data storage in Oracle Database. Other names for data blocks include Oracle blocks or pages. One data block corresponds to a specific number of bytes of physical space on disk. See also extent; segment. |
| data concurrency | 併發資料訪問 | Simultaneous access of the same data by many users. A multiuser database management system must provide adequate concurrency controls so that data cannot be updated or changed improperly, compromising data integrity. See also data consistency. |
| data consistency | 資料一致性 | A consistent view of the data by each user in a multiuser database. See also data concurrency. |
| data corruption | 資料損壞 | An error that occurs when a hardware, software, or network component causes corrupt data to be read or written. |
| data dictionary | 資料字典 | A read-only collection of database tables and views containing reference information about the database, its structures, and its users. |
| data dictionary cache | 資料字典快取 | A memory area in the shared pool that holds data dictionary information. The data dictionary cache is also known as the row cache because it holds data as rows instead of buffers, which hold entire data blocks. |
| data dictionary (DDL) lock | 資料字典（DDL）鎖定 | A lock that protects the definition of a schema object while an ongoing DDL operation acts on or refers to the object. Oracle Database acquires a DDL lock automatically on behalf of any DDL transaction requiring it. Users cannot explicitly request DDL locks. |
| data dictionary view | 資料字典檢視 | A predefined view of tables or other views in the data dictionary. Data dictionary views begin with the prefix DBA_, ALL_, or USER_. |
| data file | 資料檔案 | A physical file on disk that was created by Oracle Database and contains the data for a database. The data files can be located either in an operating system file system or Oracle ASM disk group. |
| data integrity | 資料完整性 | Business rules that dictate the standards for acceptable data. These rules are applied to a database by using integrity constraints and triggers to prevent invalid data entry. |
| data mining | 資料探勘 | The automated search of large stores of data for patterns and trends that transcend simple analysis. |
| Data Recovery Advisor | 資料恢復Advisor | An Oracle Database infrastructure that automatically diagnoses persistent data failures, presents repair options to the user, and executes repairs at the user's request. |
| data segment | 資料段 | The segment containing the data for a nonclustered table, table partition, or table cluster. See also extent. |