Chapter 5 - MIS - Mgt 472 with Dr. Harden. I got an A. PDF

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MIS - Mgt 472 with Dr. Harden. I got an A. ...

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Chapter 5 Database Processing 

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Purpose of a database is to keep track of things. Now bc of Moore’s law making the cost of data storage basically free, individuals and businesses are keeping track of lots of things. Metadata: categorizing data is needed bc information is getting more complex Data structure: relating various pieces of information Data mining/ business analytics: analyzing the information and growing insights Components of a database: o Tables: rows of records, each containing fields or columns of a single piece of information o Relationships: rules that specify how information in any particular record in one table may be related to another table record o Metadata: data that describes the data in the tables Database Management System (DBMS): also has the above parts and end users, applications for creating queries, reports, and forms, and software like Microsoft Access or SQL Server Databases are valuable. It’s important. Securing it can be difficult but a primary objective for businesses (it’s like your phonebook and all information) Database workers are highly regarded and compensated in the business world whether they develop, maintain, or administer the database. End user plays a vital role in developing any database system.

Textbook notes: 

Every time we google something we think it just works but it’s actually searching through databases to find the answer

What is the purpose of a database?   

To keep track of things Or use a spreadsheet for simple lists but not complex lists Multiple themes has database

What is a database?   

Database: a self-describing collection of integrated records Byte: character of data In databases, bytes are set in columns aka fields. Then they are grouped in rows aka records.

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The collection of data for all columns are called a row or record. A group of similar rows or records is called a table or a file A database is a collection of tables plus the relationship among the rows of those tables plus special data aka metadata that describes the structure of the database. Databases on disks Relationships among rows in tables. A key aka primary key is a column or group of columns that identifies a unique row in a table. 123 number in row student. Every table has a key. It’s a unique identifier. Foreign key – when columns are keys but they are keys to a different table then the one they reside in Relational databases: databases that carry their data in the form of tables and represent relationships using foreign keys Metadata: data that describes data. Makes a database useful Database is integrated bc the rows can be linked by their (foreign)/keys relationships

What is a database management system (DBMS)?  

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DBMS: a program used to create, process, and administer a database Businesses don’t own their own DBMS rather they license it from a software program whereas database is a collection of tables, relationships, and metadata. To add new table, developer opens metadata for the table, and adds a new row of metadata. Second function of the DBMS is to process the database. To read, insert, modify, or delete data. SQL is needed to process a database but can be used by criminals to steal data SQL aka Structured Query Language: international standard language for processing a database. 3rd function of DBMS is to provide tools to assist in the administration of the database. Database administration: involves a wide variety or activities. Like setting up security systems, permissions, passwords etc. or backing up database data,

How do database applications make databases more useful?  

Data in a database is more useful when in another format than tables. Database application: a collection of forms, reports, queries, and application programs that serves as an intermediary between users and database data.

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Database applications reformat the database table data to make it more informative and easily updated. It also provides security, maintain data consistency, and handles special cases Specific purposes of the four elements of a database application: o Forms: view data, insert new, update existing, and delete existing data o Reports: structured presentation of data using sorting, grouping, filtering, etc o Queries: search based on data values provided by the user. A request that is executed to retrieve data from a database. o Application programs: provide security, data consistency, and special purpose processing like handling out of stock situations. 1990s Traditional forms, queries, reports, and applications: applications stay on user computers, and DBMS and database reside on a server computer. Network is used to transmit traffic back and forth between the users computers and the DBMS server computer. Microsoft access is an exception bc that has the database, application, DBMS, and the database all reside on the user’s computer. Traditional forms appear in a window like display that serves its purpose but looks clunky Traditional report= static data. Format good. Browser forms, reports, queries, and applications- shared. Thin client applications that don’t need to be preinstalled on computer. The code is shared between computers. Html Dynamic Graphical queries: exciting. Criteria is created when the user clicks on a graphic. Icons More security for browser based internet rather than traditional applications. It’s a major function for browser based internet application programs Multi-user processing: multiple users processing the same database. Has its unique problems. o 2 individuals see tickets available and one purchases them while the other checks with her friend and then purchases it. One of these people will be disappointed this is called lost update problem. To prevent this, some locking must be used to coordinate the activities of users who know nothing about each other. Locking has its own issues.

o Ask IT for assistance when you feel like there is multi-user data conflicts How are data models used for database development?     

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Data modeling and database design Design of database depends on how users view their busi environment, user involvement is critical for database development Most have all the needed data to make users able to perform their jobs. Choices are endless Can be complex structure. Data model: before building a database, the developers construct a logical representations of database data. It describes the data and relationships that will be stored in the database. Aka a blueprint Database development process: interviews with users lead to database requirements, in data model. Once users approve data model, it goes to database design. Which is then put into structures, and lastly make the database. Entity- Relationship (E-R) Data Model: a tool for constructing data models. Developers use it to describe the content of the data model by defining the things (entities) that will be stored in the database and relationships among those entities. Another tool for data modeling is Unified Modeling Language (UML). Entity: is some thing that the users what to track. Order, Salesperson, Item. Always singular. Attributes: entities have this that describe the characteristics of the entity. Like OrderNumber Identifier: entities have this. Something that its value is associated with one and only one entity instance. OrderNumber is an identifier of Order bc only one Order instance has a given value to OrderNumber. Relationships: entities have relationships to each other. Order relates to customer and Salesperson. Entity relationship (E-R) diagrams: not used with design discussions. Rectangles. Used with diagrams. Vertical bar of relationship means just one department. Forked lines show more than one relation. Angled lines are crow’s feed are shorthand for multiple lines between. Aka 1:N (one to many relationships) N:M (many to many relationships) Maximum cardinality: crow’s foot notation shows max number of entities that can be involved like 1:N, N:M, and 1:1 Minimum cardinalities: yeah More on lines 181

How is a data model transformed into a database design?    

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Database design is the process of converting a data model into tables, relationships, and data constraints. The database design team transforms entities into tables and expresses relationships by defining foreign keys Complex Normalization: a foundation of database design o The process of converting a poorly structured table into two or more well structured tables. o A table is a simple construct that you may wonder how one could possibly be poorly constructed o Data integrity problems: some rows indicate the name as one thing and another in another row o It’s a serious issue because it produces incorrect and inconsistent results. Users will lose confidence in the system and it will get a poor reputation o Normalizing for data integrity- only occurs if data is duplicated. So eliminate the problem by eliminating the duplicated data. o Normalization tables eliminate data duplication but they can be slower to process. Dealing with such trade offs is an important consideration in database design. o General goal of normalization is to construct tables that every table has a single topic or themes. o Not normalized is irregular not normal data o Overall it can be slower to process. The representation of two kinds of relationships: helps to understand important design considerations o The steps involving in transforming a data model into relational database design o The database designer creates a table for each entity. The identifier of the entity is the key of the table the attribute of the entity becomes a column of the table. o Normalized to one theme then represent relationship among the tables o Use foreign keys and N:M relationships o If the data model is wrong, the database design will be wrong. o A database is a model of how the users view the business world. Users are the final judges as to what data the databse should contain and how records in that database should be related o Easiest time to change the database structure is during the data modeling stage

o Changing a relationship from one to many o many to many in a dat model is changing 1:N to N:M. o User review of the data model is crucial How can falcon security benefit from a database system?   

ACID atomic consistent isolated durable transactions

Other:    

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DBMS: uncouples programs and data, enabling data to stand on its own Database: collection of integrated records N:Many lots A column or group of columns that identifies a unique row in a table is a key primary key: a column or group of columns that identifies a unique row in the table. Record – row. Field- column, table- similar rows or records Creating a data model: step used in determining the requirements for new forms , reports, and queries during the development of database application system. Database design is after the users validate the data model. Creates a blueprint Data model is a logical representation of the data in a database that describes the data and relationships that will be stored in the database MongoDB: open source document orientated DBMS that’s used by Craigslist and Foursquare b/c it doesn’t require normalized data but manages collections of documents that have a variety of structures. Reports: used to compute values as they present data, has structured data, purpose is to structure data into a presentation using sorting, grouping, altering, and other operations. Forms: are used to read, insert, modify, and delete data Queries are requests that are executed to retrieve data from a database Database application: a collection of forms, reports, queries, and programs that process a database Database schema: database structure in a formal language. Channel is how CPU reads the instructions. Not normalized tables: have a format that can cause data integrity problems Metadata: describes the structure of a database

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Column is a group of bytes. Row is a group of related fields or columns, tables are group of similar records or rows. Normalization: the process of converting poorly structured tables into two or more well-structured tables DBMS can centralize data = differs from traditional file system A row is a group of columns A table is a group of records A database is a group of tables A spreadsheet has a single theme...