数据建模 Database Modeling:概念 (Conceptual) vs 逻辑 (Logical) vs 物理数据 (Physical) 模型 数据建模是一种使用实体关系图(ER图)记录软件系统的技术,实体关系图是公司数据库表中数据结构的表示。它是公司业务需求的非常有力的表达。数据模型有多种用途,从高级概念模型、逻辑到物理数据模型,通常由实体关系图表示...
Logical and physical database design within a full-text environmentC D MichelsenDon Shafer
database design in Step1 and Step2 (i.e., create table scripts and the ERD). Set up all the tables and their constraints in the correct order before you load any data into the database. In summary, the grader should be able to verify your design convincingly, comprehensively and with e...
Logical database design bridges the gap between the conceptual and physical levels. Here, designers translate the conceptual model into a more detailed representation, focusing on data structures, relationships, and constraints. The logical design is independent of any specific database management s...
Which three statements are true concerning logical and physical database structures? (Choose three.) A. All tablespaces may have one or more data files B. The extents of a segment must always reside in the same datafile C. A smallfile tablespace might be bigger than a bigfile tablespace ...
You can use data description specifications (DDS) to define physical and logical database files. Defining a physical file using DDS You use file-level, record-level, field-level, and key-field-level entries to define a physical file with data description specifications (DDS). ...
(3) the internal schema, which describes the storage structures and indexing methods that describe the database files. Physical data independence is defined as the capability to change the internal schema (storage structures/indexes) without having to change the conceptual schema. Logical database ...
The sum of "db block gets" plus "consistent gets".This includeslogicalreadsof database blocks from either the buffer cache or process private memory. db block gets Number of times a CURRENT block was requested consistent gets Number of times a consistent read was requested for a block. ...
This information gets transformed into a logical (or physical) database design. 该信息转换成逻辑的(或物理的)数据库设计。 www.ibm.com 2. Database model: Encapsulates a logical and physical database design for this specific project. 数据库模型:封装供此特定项目使用的逻辑和物理数据设计。 www.ibm...
As its name implies, structured data requires proper design; to this end, two fundamental approaches to structureddata modelinghave become fixtures in the enterprise database world: logical data models and physical data models. Logical data model.These high-level, abstract representation of data empha...