Object oriented Model

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● Overview
● DBMS
● Why we need database?
● Data abstraction
● Instance of schemes
● Types of database models
● Data models- Continue
● Entity-Relationship (E-R) model
● Aggregation
● Generalization
● E-R diagram Table
● Mapping constraints
● Object oriented Model
● Object oriented Model-Continue
● Object Oriented Model-Continue
● Object oriented Model-Continue
● Hierarchical Model
● Network Model
● Relational model
● Reasons to use Relational Model
● Relational DBMS
● Relationships between Tables
● Relational DBMS
● One-to-One
● Relational DBMS
● One-to-Many
● Many-to-One
● Data Definition Language (DDL)
and Data Manipulation Language (DML)
● Types of DML
● Query language (QL)
● Relational algebra (RA)
● Structured Query Language (SQL)
● Setting up User Accounts and Privileges
● Creating Tables
● Field types
● Creating and Displaying Indexes
● Exporting and Importing Data
● Relational Database design
● Database quality
● Storage Capacity Terminology
● Boolean expressions
● AND
● Boolean Operators
● OR
● Boolean Operators
● NOT
● Boolean Operators
● Operators
● Query Syntax
● Query Syntax Examples
● Common Query Syntax Errors
● Query Syntax
● References

نوع زبان: انگلیسی حجم: 0.34 مگا بایت
نوع فایل: اسلاید پاورپوینت تعداد اسلایدها: 77 صفحه
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گروه موضوعی: زمان استخراج مطلب: 2019/06/05 09:02:02

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عبارات مهم استفاده شده در این مطلب

عبارات مهم استفاده شده در این مطلب

object, ., database, model, datum, entity, level, relationship, e, student, set, diagram,

توجه: این مطلب در تاریخ 2019/06/05 09:02:02 به صورت خودکار از فضای وب آشکار توسط موتور جستجوی پاورپوینت جمع آوری شده است و در صورت اعلام عدم رضایت تهیه کننده ی آن، طبق قوانین سایت از روی وب گاه حذف خواهد شد. این مطلب از وب سایت زیر استخراج شده است و مسئولیت انتشار آن با منبع اصلی است.

https://faculty.uaeu.ac.ae/myagoub/gis/Database%5B1%5Dweek3.ppt

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عبارات پرتکرار و مهم در این اسلاید عبارتند از: object, ., database, model, datum, entity, level, relationship, e, student, set, diagram,

مشاهده محتوای متنیِ این اسلاید ppt

مشاهده محتوای متنیِ این اسلاید ppt

database management system dbms by dr. mohamed yagoub mohamed e mail myagoub@hotmail.com url http www.angelfire.com mo yagoub overview why we need database database concept types of database models relational database dbms dbms is a collection of data database and programs to access that data. the goal of dbms is to store retrieve and display information key characteristics of dbms are performance store large volume of database share data access provide security authorization remove redundancy normalization and provide concurrent access different users at the same time . why we need database without database gis is cartography electronic map no database no spatial analysis why we need database principles of gis database and gis data abstraction physical level describe how the data are actually store word or bytes conceptual level describe what data are actually stored in the database structure . it gives schematic representation of phenomena view level describe only a part of the entire database. many users of the database may be concerned with a subset of information. the system may provide many views for the same database data abstraction continue conceptual level logical level different users for the same database data abstraction view level instance of schemes the collection of database at a particular moment is called the instance of the database the overall design of the database is called the database scheme types of database models data model is a collection of conceptual tools for describing data data relationship data semantics and consistency constraints. there are mainly three types of models object based logical models are used to describe data at the conceptual and view level. example of these the entity relationship model and object oriented model data models continue record based logical models are used to describe data at the conceptual and view level. example of these are network model hierarchical model and relational model. physical data models are used to describe data at the physical level bytes and words . it is mainly deal with hardware. entity relationship e r model it is based on simulation of the real world which consists of basic objects called entities and relationship among these objects the overall logical data structure of a database can be expressed graphically by an e r diagram. which consists of rectangle entity ellipse attribute diamond relationship and lines. e r diagram for customer customacct relationship associate a customer with each account he has ۳ tables can represent the above relation ۱ ۲ ۳ aggregation aggregation is an abstraction through which relationships are treated as higher level entities i.e. express relationships among relationships e r diagram with aggregation ۵ tables can represent the diagram generalization in e r diagram generalization is depicted through a triangle labeled isa is a . the attribute of higher level entity are said to be inherited by lower level entity. e.g. both saving and checking account inherit the attributes of account e r diagram with generalization ۳ tables can represent the diagram e r diagram table an entity e with attributes a۱..an can be represented by a table called e with n columns for each attribute. each row in this table corresponds to one entity of the entity set e let d۱ set of all account number d۲ set of all balance any row consists of ۲ tuples v۱ v۲ e.g. ۲۵۵ ۳ the set of all possible rows is the cartesian product of d۱ and d۲ i.e. d۱ x d۲ for a table with n columns the total number of rows d۱ x d۲ x ..x dn ۱ x dn mapping constraints mapping cardinalities express the number of entities to which another entity can be associated via a relationship for a binary relationship set r between entity set a and b the mapping can be one one ۱ ۱ one many ۱ m many one m ۱ and many many m m ۱ m relation object oriented model the basic unit that an object oriented oo dbms manages is the object. it is based on four basic concepts of abstraction classification mapping of several objects instances to common class generalization group several classes which have the same properties in common roads railway transportation network object oriented model continue association relation between similar objects is considered a higher level set object aggregation objects which consist of several other objects composed objects object oriented model continue oo model uses objects rather than records to manage data an object is a collection of data elements and operations that together are considered a single entity an object has associated with it a set of variables that contain the data for the object a set of messages to which the object respond and a method which response to the message object oriented model continue once the structure is setup the details of it need not be user visible this approach has the attraction that query is very natural a geographic data handling systems employ this model are tigris daplex and probe it is application in gis is recommended object oriented model continue objects are typed and the format and operations of an object instance are the same as some object prototype example of an object might be a lake list of border chain c۱ c۲ c۳ cn list of nodes n۱ n۲ n۳ nn attribute depth soil type object oriented model continue for example student can be a superclass. first and second year student may represented by a classes that are specialization of a student class variables and methods specific to first year students are associated with fist year student class. variables and methods that apply both to first and second year students are associated with student class. the variables associated with each class may be student name id address first year student subject second year student practical course hierarchical model based on tree structure child parent no element can have more than one parent requires knowledge by the user of the actual storage scheme used by the dbms examples of database are system۲ and ims not commonly …

کلمات کلیدی پرکاربرد در این اسلاید پاورپوینت: object, ., database, model, datum, entity, level, relationship, e, student, set, diagram,

این فایل پاورپوینت شامل 77 اسلاید و به زبان انگلیسی و حجم آن 0.34 مگا بایت است. نوع قالب فایل ppt بوده که با این لینک قابل دانلود است. این مطلب برگرفته از سایت زیر است و مسئولیت انتشار آن با منبع اصلی می باشد که در تاریخ 2019/06/05 09:02:02 استخراج شده است.

https://faculty.uaeu.ac.ae/myagoub/gis/Database%5B1%5Dweek3.ppt

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