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chapter 3 - database systems, data warehouses, and data marts
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- 1chapter 3 - database systems, data warehouses, and data marts-ads
- 2database- is a collection of related data that is stored in a central location or in multiple locations
-can consist of one file, usually consists of many - 3data hierarchy-is the structure and organization of data, which involves fields, records, and files
- 4database management system (DBMS)-is software for creating, storing, maintaining, and accessing database files. DBMS makes using databases more effiicient
- 5note-data used to be stored what was called "flat files" bc they were not arranged in a hierarchy, creating data in more then one place called data rebundancy.
- 6user to DBMS to databaseusers to DBMS
-user makes a request for information
DBMS to databases
-DBMS searches the database
database back to DBMS
-DBMS retrieves the information
DBMS to users
-DBMS returns information to the user - 7advantages of a database over a flat file-more information can be generated from the same data
-complex requests can be handled more easily
-data redundancy is eliminated or minimized
-data management is improved - 83-1a) types of data in a database-interal and external and used to generate BI
- 93-1b)methods of accessing files-sequential, random, or indexed sequential method
- 10sequential access file structure-record in files are organized and processed in numerical or sequential order, typically the order in which they were entered
-to access 10, must go 1 thru 9 - 11random access file structure-records can be accessed in any order, regardless of their physical locations in storage media. this method of fast and very effective when a small number of records need to be processed daily or weekly
- 12notes-disks are random access, tapes are sequential
- 13indexed sequential access method (ISAM)-records can be accessed sequentially or randomly, depending on the number being accessed. for a small number random access is used, and for a large number, sequential access is used
- 143.2- logical database design two ways information is viewed in a database-physical and logical
- 15physical view-involves how data is stored on and retrieved from storage media, such as hard disks, magnetic tapes, or CD's
-only one physical view of data - 16logical view-involves how information appears to users and how it can be organized and retrieved
- 17first step of designing databases: data modeldefn - determines how data is created, represented, organized, and maintained. it usually contains 1,2, and 3/
1) data structures- describes how data is organized and relationships among records
2)operations - describes methods, calculations, and so forth that can be performed on data, such as updating and querying data
3)integrity rules - defines the boundaries of a database, such as maximum and minimum values allowed for a field, constraints, and access methods - 18two other common data models are hierarchical and network- not used as much anymore
- 19hierarchical modela tree, node at top is the root, child all others have a parent, nodes with the same parent are twins/siblings
- 20network model-is similar to the hierarchical model, but records are organized differently. unlike the hierarchical model, each record in the network model can have multiple parent and child records
- 213-2a) the relational model-uses a two-dimensional hierarchical model, but records are organized differently. unlike the hierarchical model, each record in the network model can have multiple parent and child records
- 22note about relational model-rows are records (tuples)
-columns are field (attributes) - 23data dictionary-stores definitions, such as data types for fields, default values, and validation rules for data in each field
- 24primary key-uniquely identifies every record in a relational database. examples include student ID numbers, account numbers, social security numbers, and invoice numbers
- 25foreign key-is a field in a relational table that matches the primary key column of another table. it can be used to cross-reference tables.
- 26normalization-improves database efficiency by eliminating redundant data and ensuring that only related data is stored in a table.
- 27note main three types of operations used to retrieve data in a relational system-select - retrieves Data in table based on certain criteria (conditions)
project - compares table by eliminating columns (fields) according to certain criteria
join - combines two tables based on a common field - 283.3 - components of a DBMS discusses,-database engine
-data definition
-data manipulation
-application generation
-data administration - 293-3a) database engine-heart of the DBMS system
- is responsible for data storage, manipulation, and retrieval - 303-3b) data definition- used to create and maintain the data dictionary
- 313-3c) data manipulation-used to add, delete, modify, and retrieve records from a database
- 32structured query language-is a standard fourth-generation query language used by many DBMS packages, such as oracle 12c and mircosoft SQL server. SQL consists of several keywords specifying actions to take
- 33query by example-you request data from a database by constructing a statement made up of query forms. with Current graphical databases, you simply click to select query forms instead of having to remember keywords, as you do with SQL. you can add AND, OR, and NOT operators to the QBE form to fine-tune the query
- 343-3d) application generation-the applicatio generation component is used to design elements of an application using a database, such as data entry screens, interactive menus, and interfaces with other computer languages
- 353-3e) data administration-used by IT professionals for backup, retrieval, security, and change managemnet
also, uses create, read,update, and delete (CRUD) - 36database administrators-found in large organizations, design, and set up databases, establish security measures, develop recovery procedures, evaluate database performance, and add and fine-tune database functions
- 373-4)recent trends in database design and use 3-4a) data-driven web sites- acts as an interface to a database, retrieving data for users and allowing users to enter data in the database
-without this then web site designers must edit the HTML - 383-4b) disturbed databases defn - disturbed database management system (DDBMS)-stores data on multiple servers throughout an organizations
- 39three approaches to setting up a DDBMS-fragmentation
-replication
-allocation - 40fragmentation-approach to a disturbed DBMS addresses how tables are divided among multiple locations. there are three variations, horizontal, vertical, and mixed
- 41replication-approach to a distributed DBMS has each site store a copy of the data in the organization's databases
- 42allocation-approach to a distributed DBMS combines fragmentation and replication, with each site storing the data it uses most often
- 433-4c) object-oriented databases- both data and their relationships are contained in a single object. An object consists of attributes and methods that can be performed on the objects data
- 44encapsulation-refers to the grouping into a class of various objects along with their attributes and methods - meaning, grouping, related items into a single unit. this helps handle more complex types of data, such as images and graphs
- 45inheritance-refers to new objects being created faster and more easily by entering new data in attributes
- 463.5 - data warehouses definitions-is a collection of data from a variety of sources used to support decision-making applications and generate business intelligence
- 47note-typically have subject orientated, integrated, time variant, type of data, purpose
- 48data warehouse configuration-input, extraction, transformation, and loading (ETL)
- 493-5a)input-input come from a variety of sources
-together these data sources provide the input a data warehouse needs to perform analyses and generate reports - 503-5b)ETL-refers to the processes used in a data warehouse. it includes extracting data from outside sources, transforming . it to fit operational needs, and loading it into the end target (database or data warehouse)
- 513-5c)storage-organized in a data warehouse as raw data, summary data, or metadata
raw data - is information in its original form
summary data - gives users subtotals of various categories
metadata- information about data - its content, quality, condition, origin, and other characteristics - 523-5d) Output online transaction processing (OLTP)-is used to facilitate and manage transaction-oriented applications, such as point-of-sale, data entry, and retrieval transaction processing. it generally uses internal data and responds in real time
- 53Online transction processing-is used to facilitate and manage transaction-oriented applications, such as point- of -sale, data entry, and retrieval transaction processing. It generally uses internal data not responds in real time
- 54online analytical processing-generates business intelligence. it uses multiple sources of information and provides multidimensional analysis , such as viewing data based on time, product, and location
- 55data-mining analysis-is used to discover patterns and relationships
- 56data marts-is usually a smaller version of a data warehouse, used by a single department or function
- 57data marts advantages over warehouse-access to data is often faster because of their smaller size
-improved respond time to users
-easier to create
-they are less expensive
-users are targeted better, because a data mart is designed for a specific department or divison - 583-7 - business analytics defndefn - uses data and statistical methods to gain insight into the data and provide decision makers with information they can act on
- 59three types of BA methods and two other data terms-descriptive (reactive), predictive(proactive), and prescriptive (as the name suggests)
web data
mobile data - 603.8 - the big data era defn-is data so voluminous that conventional computing methods are not able to efficiently process and manage it
- 61three dimensions to big data-volume, variety, and velocity
- 62volume-sheer amount of transactions
- 63varietystructured data - customers' product ratings between 1 and 5
unstructured data - call center conversations or customer complaints - 64velocity-this refers to the speed with which the data has to be gathered and processed
- 653-8a) who benefits from big data?-retail, financial services, advertising, government, manufacturing, media and telecommunications, energy, healthcare
- 66note-privacy risks associated with big data
-tools such as social media, and mobile data - 673-9 database marketing defintion-uses an organization's database of customers potential customers to promote products or services
- 68note-examples of data marketing is readers digest, american express, mail-order catalog companies, and credit bureaus
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- information systems Fichas sobre chapter 3 - database systems, data warehouses, and data marts, creado por nathan fulcher el 28/09/2019.
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