relational data model concepts

The Relational Data Model and Relational Database Constraints

Ngày tải lên : 12/05/2014, 11:55

... key. Relational Model Concepts  The relational Model of Data is based on the concept of a Relation.  A Relation is a mathematical concept based on the ideas of sets.  The strength of the relational ... has three tuples. Relational Model Concepts  The model was first proposed by Dr. E.F. Codd of IBM in 1970 in the following paper: "A Relational Model for Large Shared Data Banks," ... Domain Table Definition Schema of a Relation Populated Table Extension The Relational Data Model and Relational Database Constraints

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Chương 3: Mô hình quan hệ (Relational Data Model) potx

Ngày tải lên : 05/07/2014, 16:20

... thuộc tính của một quan hệ luôn là siêu khóa. 1 1 CƠ SỞ DỮ LIỆU Chương 3 MÔ HÌNH QUAN HỆ (Relational Data Model) 2 Chương 3 MÔ HÌNH QUAN HỆ I. Một số khái niệm Định nghóa quan hệ Khóa của quan hệ II....

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Oracle Data Guard Concepts and Administration

Ngày tải lên : 26/10/2013, 22:15

... Standby Databases 7-11 7.2.1 Switchovers Involving a Physical Standby Database 7-11 7.2.2 Failovers Involving a Physical Standby Database 7-14 Data Guard Services 1-4 Oracle Data Guard Concepts ... the redo data to be archived first at the standby database. ■ Role Management Services Change the role of a database from a standby database to a primary database, or from a primary database ... standby database is created and configured, Data Guard automatically maintains the standby database by transmitting primary database redo data to the standby system, where the redo data is...

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Oracle9i Data Mining Concepts Release 9.2.0.2 October 2002 Part No. A95961-02 Oracle9i Data

Ngày tải lên : 06/11/2013, 01:15

... Basic ODM Concepts 1-1 1 Basic ODM Concepts Oracle9i Data Mining (ODM) embeds data mining within the Oracle9i database. The data never leaves the database — the data, data preparation, model building, ... preprocessing as the data used to build the model. ODM Algorithms Basic ODM Concepts 1-15 After building the specified models, Model Seeker evaluates each model by testing and calculating lift. Model Seeker ... 1.2 Oracle9i Data Mining Components Oracle9i Data Mining has two main components: ■ Oracle9i Data Mining API ■ Data Mining Server (DMS) 1.2.1 Oracle9i Data Mining API The Oracle9i Data Mining...

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Tài liệu Activity 4.2: Creating a Logical Data Model ppt

Ngày tải lên : 21/12/2013, 06:16

... Activity 4.2: Creating a Logical Data Model In this activity, you will use the skills learned in this module to define the relationships within a logical data model and produce a sample ER diagram ... Activity 4.2: Creating a Logical Data Model 19 Exercise 2: Determining Cardinality and Existence In this exercise, you will ... activity, you will be able to: ! Identify relationships between entities. ! Create a logical data model. Before You Begin This activity will take place in small groups with a class discussion...

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Tài liệu NoSQL Database Technology: Post-relational data management for interactive software systems docx

Ngày tải lên : 19/02/2014, 12:20

... their own database technologies. These “NoSQL” databases, each eschewing the relational data model, are a far better match for the needs modern interactive software systems. NOSQL DATABASE ... Denormalizing Before storing data in an RDBMS, a schema must be created dening precisely what data can be stored in the database and the relationships between data elements. Data is decomposed into ... easier and allows for rapid changes in the data model. Of course, just about all relational database functionality is lost in the process (though if the database is sharded, much of the functionality...

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Báo cáo khoa học: "A Flexible Stand-Off Data Model with Query Language for Multi-Level Annotation" ppt

Ngày tải lên : 08/03/2014, 04:22

... associative relations representing e.g. coreference. 2 The Data Model We propose a stand-off data model implemented in XML. The basedata is stored in a simple XML ﬁle 1 The current release version ... token queries exactly one basedata element (i.e. word) or one markable. 3.1 Query Tokens Basedata elements can be queried by matching reg- ular expressions. Each basedata query token con- sists ... of the relations of their basedata elements. While it has become common practice to use the stand-off mechanism to relate several annotation levels to one basedata ﬁle, it is also not un- common...

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Báo cáo khoa học: "Towards A Modular Data Model For Multi-Layer Annotated Corpora" docx

Ngày tải lên : 17/03/2014, 04:20

... exists. 2 Data models There are three purposes data models can serve. The ﬁrst purpose is context suitability. A data model used for this purpose must reﬂect as well as possible the data the user ... low level data storage model rather than a high level annotation data model. A high level query language is necessary to get a good user acceptance and to achieve independence from lower level data models ... annotated multi-modal data. NXT is based on the NITE Object Model (NOM) which is an extension of the XML data model. NOM features a similar separa- tion of tiers as the PACE-Ling data model, but is more...

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The POSTGRES Data Model

Ngày tải lên : 28/04/2014, 13:32

... extended with user-deﬁned procedures. Section 5 compares the model with other data models and section 6 summarizes the paper. 2. Data Model A database is composed of a collection of relations that ... object-oriented model, but it does so without discarding the relational model and without having to introduce a new confusing terminology. 6. Summary The POSTGRES data model uses the ideas of abstract data ... of abstract data types, data of type procedure, and inheritance to extend the relational model. These ideas can be used to simulate a variety of semantic data modeling concepts (e.g., aggregation...

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Data Mining Concepts and Techniques phần 1 potx

Ngày tải lên : 08/08/2014, 18:22

... Advanced database systems include object -relational databases and speciﬁc application-oriented databases, such as spatial databases, time-series databases, text databases, and multimedia databases. ... data repository, as well as to transient data, such as data streams. Thus the scope of our examination of data repositories will include relational databases, data warehouses, transactional databases, ... constructed for relational databases. An ER data model represents the database as a set of entities and their relationships. Consider the following example. Example 1.1 A relational database for...

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Data Mining Concepts and Techniques phần 2 ppsx

Ngày tải lên : 08/08/2014, 18:22

... section describes both data integration and data transformation. 2.4.1 Data Integration It is likely that your data analysis task will involve data integration, which combines data from multiple ... 97 2.7 Summary Data preprocessing is an important issue for both data warehousing and data mining, as real-world data tend to be incomplete, noisy, and inconsistent. Data preprocessing includes data cleaning, ... cleaning, data integration, data transformation, and data reduction. Descriptive data summarization provides the analytical foundation for data preprocessing. The basic statistical measures for data...

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Data Mining Concepts and Techniques phần 3 docx

Ngày tải lên : 08/08/2014, 18:22

... warehousing technology. 3.3.4 Metadata Repository Metadata are data about data. When used in a data warehouse, metadata are the data that deﬁne warehouse objects. Figure 3.12 showed a metadata repository within ... the ﬁeld of data mining, substantial research has been performed for data mining on various platforms, including transaction databases, relational databases,spatial databases, text databases, ... Most data mining tools need to work on integrated, consistent, and cleaned data, which requires costly data cleaning, data integration, and data transformation as preprocessing steps. A data warehouse...