logging in or signing up data base architecture mirzag Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 3647 Category: Education License: All Rights Reserved Like it (2) Dislike it (0) Added: January 24, 2010 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... By: Blueflame (25 month(s) ago) Great work you did buddy. Saving..... Post Reply Close By: mirzag (24 month(s) ago) thax for gr8 appreciation Saving..... Edit Comment Close By: csoumy (25 month(s) ago) wonderful ppt.. this was exactly what I wanted.. thank you :) Saving..... Post Reply Close By: mirzag (24 month(s) ago) thx for luk Saving..... Edit Comment Close By: jojo_alj (28 month(s) ago) hi,thenk you Saving..... Post Reply Close By: mirzag (26 month(s) ago) any time...this ppt file is updated also chk em..thats gud also Saving..... Edit Comment Close Premium member Presentation Transcript Slide 1: DATA BASE ARCHITECTURE DBMS presenters : presenters S B Mirza 1314 Neelma 1322 Mehwish 1312 Amna nazir 1310 What is a database : What is a database A database is any organized collection of data. Some examples of databases you may encounter in your daily life are: a telephone book T.V. Guide airline reservation system motor vehicle registration records papers in your filing cabinet files on your computer hard drive. What is the ultimate purpose of a database management system? : What is the ultimate purpose of a database management system? Data Information Knowledge Action Is to transform Slide 5: Three-Level Database Architecture External Level Conceptual Level Internal Level Slide 7: EXTERNAL LEVEL (highest level) • The user’s view of the database. • Consists of a number of different external views of the DB. • Describes part of the DB for particular group of users. • Provides a powerful and flexible security mechanism by hiding parts of the DB from certain users. The user is not aware of the existence of any attributes that are missing from the view. • It permits users to access data in a way that is customized to their needs, so that the same data can be seen by different users in different ways, at the same time. Slide 8: CONCEPTUAL LEVEL . The logical structure of the entire database as seen by DBA. . What data is stored in the database. . The relationships among the data. . Complete view of the data requirements of the organization, independent of any storage consideration. . Represents: - Íentities, attributes, relations - constraints on data - semantic information on data - security, integrity information Supports each external view: any data available to a user must be contained in, or derivable from the conceptual level. Slide 9: INTERNAL LEVEL • Physical representation of the DB on the computer. • How the data is stored in the database. • Physical implementation of the DB to achieve optimal run– time performance and storage space utilization. - Storage space allocation for data and indexes - Record description for storage - Record placement - Data compression, encryption Slide 11: Mappings: The process to convert a request (from external level) and the result between view levels is called mapping. Slide 12: There are two types of mapping. External-Conceptual mapping Conceptual-Internal mapping Slide 13: conceptual/internal mapping: to find the actual record (combinations) in physical storage that constitute a logical record in the conceptual schema. external/conceptual mapping: map names in the user’s view onto the relevant part of the conceptual schema. Slide 14: Data Independece & Data Dictionary DATA INDEPENDENCE : DATA INDEPENDENCE The disjointing of data descriptions from the application programs (or user-interfaces) that uses the data is called data independence . Data independence is the type of data transparency that matters for a centralized DBMS. It refers to the immunity of user applications to make changes in the definition and organization of data Types of data independence. : Types of data independence. There are two kinds of data independence. Physical data independence Logical data independence Physical data independence : Physical data independence The ability to change the physical schema without changing the logical schema is called physical data independence. For example, a change to the internal schema, such as using different file organization or storage structures, storage devices, or indexing strategy, should be possible without having to change the conceptual or external schemas. Modifications at this level are usually to improve performance . Logical data independence : Logical data independence The ability to change the logical (conceptual) schema without changing the External schema is called logical data independence. For example, the addition or removal of new entities, attributes, or relationships to the conceptual schema should be possible without having to change existing external schemas or having to rewrite existing application programs. Data Dictionary/Directory Systems : Data Dictionary/Directory Systems The Data Dictionary/Directory System (DD/DS), consists of utilities and systems necessary to catalog, document, manage, and use metadata. In other words: A data dictionary is a reserved space within a database which is used to store information about the database itself. A data dictionary may contain information such as: : A data dictionary may contain information such as: Database design information Stored SQL procedures User permissions User statistics Database process information Database growth statistics Database performance statistics Slide 23: Data Languages Data Definition Language (DDL): : Data Definition Language (DDL): Used to specify a database scheme as a set of definitions expressed in a DDL DDL statements are compiled, resulting in a set of tables stored in a special le called a data dictionary or data directory. The data directory contains metadata (data about data) The storage structure and access methods used by the database system are speci ed by a set of definitions in a special type of DDL called a data storage and definition language. basic idea: hide implementation details of the database schemes from the users. Data Manipulation Language (DML) : Data Manipulation Language (DML) Data Manipulation is: o Retrieval of information from the database o insertion of new information into the database o deletion of information in the database o modification of information in the database A DML is a language which enables users to access and manipulate data. The goal is to provide ecient human interaction with the system. Types of DML : Types of DML There are two types of DML Non-Procedural DML Procedural DML Non-Procedural DML : Non-Procedural DML A high-level or non-procedural DML allows the user to specify what data is required without specifying how it is to be obtained. The end-users use a high-level query language to specify their requests to DBMS to retrieve data. Usually a single statement is given to the DBMS to retrieve or update multiple records. The DBMS translates a DML statement into a procedure that manipulates the set of records. The examples of non-procedural DMLs are SQL and QBE (Query-By-Example) Procedural DML : Procedural DML A low-level or procedural DML allows the user, i.e. programmer to specify what data is needed and how to obtain it. This type of DML typically retrieves individual records from the database and processes each separately. In this language, the looping, branching etc. statements are used to retrieve and process each record from a set of records. The programmers use the low-level DML. You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
data base architecture mirzag Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 3647 Category: Education License: All Rights Reserved Like it (2) Dislike it (0) Added: January 24, 2010 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... By: Blueflame (25 month(s) ago) Great work you did buddy. Saving..... Post Reply Close By: mirzag (24 month(s) ago) thax for gr8 appreciation Saving..... Edit Comment Close By: csoumy (25 month(s) ago) wonderful ppt.. this was exactly what I wanted.. thank you :) Saving..... Post Reply Close By: mirzag (24 month(s) ago) thx for luk Saving..... Edit Comment Close By: jojo_alj (28 month(s) ago) hi,thenk you Saving..... Post Reply Close By: mirzag (26 month(s) ago) any time...this ppt file is updated also chk em..thats gud also Saving..... Edit Comment Close Premium member Presentation Transcript Slide 1: DATA BASE ARCHITECTURE DBMS presenters : presenters S B Mirza 1314 Neelma 1322 Mehwish 1312 Amna nazir 1310 What is a database : What is a database A database is any organized collection of data. Some examples of databases you may encounter in your daily life are: a telephone book T.V. Guide airline reservation system motor vehicle registration records papers in your filing cabinet files on your computer hard drive. What is the ultimate purpose of a database management system? : What is the ultimate purpose of a database management system? Data Information Knowledge Action Is to transform Slide 5: Three-Level Database Architecture External Level Conceptual Level Internal Level Slide 7: EXTERNAL LEVEL (highest level) • The user’s view of the database. • Consists of a number of different external views of the DB. • Describes part of the DB for particular group of users. • Provides a powerful and flexible security mechanism by hiding parts of the DB from certain users. The user is not aware of the existence of any attributes that are missing from the view. • It permits users to access data in a way that is customized to their needs, so that the same data can be seen by different users in different ways, at the same time. Slide 8: CONCEPTUAL LEVEL . The logical structure of the entire database as seen by DBA. . What data is stored in the database. . The relationships among the data. . Complete view of the data requirements of the organization, independent of any storage consideration. . Represents: - Íentities, attributes, relations - constraints on data - semantic information on data - security, integrity information Supports each external view: any data available to a user must be contained in, or derivable from the conceptual level. Slide 9: INTERNAL LEVEL • Physical representation of the DB on the computer. • How the data is stored in the database. • Physical implementation of the DB to achieve optimal run– time performance and storage space utilization. - Storage space allocation for data and indexes - Record description for storage - Record placement - Data compression, encryption Slide 11: Mappings: The process to convert a request (from external level) and the result between view levels is called mapping. Slide 12: There are two types of mapping. External-Conceptual mapping Conceptual-Internal mapping Slide 13: conceptual/internal mapping: to find the actual record (combinations) in physical storage that constitute a logical record in the conceptual schema. external/conceptual mapping: map names in the user’s view onto the relevant part of the conceptual schema. Slide 14: Data Independece & Data Dictionary DATA INDEPENDENCE : DATA INDEPENDENCE The disjointing of data descriptions from the application programs (or user-interfaces) that uses the data is called data independence . Data independence is the type of data transparency that matters for a centralized DBMS. It refers to the immunity of user applications to make changes in the definition and organization of data Types of data independence. : Types of data independence. There are two kinds of data independence. Physical data independence Logical data independence Physical data independence : Physical data independence The ability to change the physical schema without changing the logical schema is called physical data independence. For example, a change to the internal schema, such as using different file organization or storage structures, storage devices, or indexing strategy, should be possible without having to change the conceptual or external schemas. Modifications at this level are usually to improve performance . Logical data independence : Logical data independence The ability to change the logical (conceptual) schema without changing the External schema is called logical data independence. For example, the addition or removal of new entities, attributes, or relationships to the conceptual schema should be possible without having to change existing external schemas or having to rewrite existing application programs. Data Dictionary/Directory Systems : Data Dictionary/Directory Systems The Data Dictionary/Directory System (DD/DS), consists of utilities and systems necessary to catalog, document, manage, and use metadata. In other words: A data dictionary is a reserved space within a database which is used to store information about the database itself. A data dictionary may contain information such as: : A data dictionary may contain information such as: Database design information Stored SQL procedures User permissions User statistics Database process information Database growth statistics Database performance statistics Slide 23: Data Languages Data Definition Language (DDL): : Data Definition Language (DDL): Used to specify a database scheme as a set of definitions expressed in a DDL DDL statements are compiled, resulting in a set of tables stored in a special le called a data dictionary or data directory. The data directory contains metadata (data about data) The storage structure and access methods used by the database system are speci ed by a set of definitions in a special type of DDL called a data storage and definition language. basic idea: hide implementation details of the database schemes from the users. Data Manipulation Language (DML) : Data Manipulation Language (DML) Data Manipulation is: o Retrieval of information from the database o insertion of new information into the database o deletion of information in the database o modification of information in the database A DML is a language which enables users to access and manipulate data. The goal is to provide ecient human interaction with the system. Types of DML : Types of DML There are two types of DML Non-Procedural DML Procedural DML Non-Procedural DML : Non-Procedural DML A high-level or non-procedural DML allows the user to specify what data is required without specifying how it is to be obtained. The end-users use a high-level query language to specify their requests to DBMS to retrieve data. Usually a single statement is given to the DBMS to retrieve or update multiple records. The DBMS translates a DML statement into a procedure that manipulates the set of records. The examples of non-procedural DMLs are SQL and QBE (Query-By-Example) Procedural DML : Procedural DML A low-level or procedural DML allows the user, i.e. programmer to specify what data is needed and how to obtain it. This type of DML typically retrieves individual records from the database and processes each separately. In this language, the looping, branching etc. statements are used to retrieve and process each record from a set of records. The programmers use the low-level DML.