Database Management Dr. Yan Quan Liu ILS, SCSU Unit 10 Database Management Dr. Yan Quan Liu ILS, SCSU KNOW THE DIFFERENCES BETWEEN THE FOUR TYPES OF DATABASES AND BE ABLE TO GIVE EXAMPLES

A system for organizing information Database Management System (DBMS) Design of Integrated Library Systems Guide to library automated systems, library software, hardware configurations may be found at: http://www.itcompany.com/inforetriever/sys.htm. What is MARC? What is Z39.50 Protocol and why is it important? 9/19/2018 ILS 501 / Dr. Liu, SCSU

Representation It allows us to reach conclusions about the thing being represented by looking only at the representing world. 9/19/2018 ILS 501 / Dr. Liu, SCSU

Representation as mappings A representation is something that stands for something else. it is a kind of a model of the thing it represents. distinguishing between a representing world and a represented world. The representing world must mirror some aspects of the represented world. 9/19/2018 ILS 501 / Dr. Liu, SCSU

Representational system What the represented world is, What aspects of the represented world are being modeled, What aspects of the representing world are doing the modeling, What the correspondences are between the two worlds. 9/19/2018 ILS 501 / Dr. Liu, SCSU

Representational system Metadata scheme Classification Subject heading Index Bibliography …… 9/19/2018 ILS 501 / Dr. Liu, SCSU

Data vs. information: What is the difference? What is information? Information is data that have been organized and communicated in a coherent and meaningful manner. Data is converted into information, and information is converted into knowledge. Knowledge; information evaluated and organized so that it can be used purposefully. What is data? Data can be defined in many ways. Information science defines data as unprocessed information. 9/19/2018 ILS 501 / Dr. Liu, SCSU

What is database? An organized collection of integrated files. A shared collection of logically related data, designed to meet the information needs of an organization. A collection of information organized in a way that a computer program can quickly select desired pieces of data. Examples ? 9/19/2018 ILS 501 / Dr. Liu, SCSU

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.  9/19/2018 ILS 501 / Dr. Liu, SCSU

Why do we need a database? Keep records of our: Clients Staff Volunteers To keep a record of activities and interventions; Keep sales records; Develop reports; Perform research Longitudinal tracking 9/19/2018 ILS 501 / Dr. Liu, SCSU

What is the ultimate purpose of a database management system? Is to transform Data Information Knowledge Action 9/19/2018 ILS 501 / Dr. Liu, SCSU

How is data structured when it is stored? Data storage hierarchy consists of the levels of data stored in a computer. bits, bytes, fields, records, files & databases Bits and bytes are the building blocks for representing data, whether it is being processed, stored, or telecommunicated. Bit – the one or the zero Byte – is the number or letter represented by the one or zero Fields – a place to input data usually in bytes Records – several fields Files – Databases – 9/19/2018 ILS 501 / Dr. Liu, SCSU

What is field? Field - a unit of data consisting of one or more characters. It usually contains a fact about a person, place, thing or event. A Key Field contains unique information so that it can be easily recognized and processed, and not be confused with another record. 9/19/2018 ILS 501 / Dr. Liu, SCSU

What is record? Record - a collection of related fields. e.g. name, address and social security number 9/19/2018 ILS 501 / Dr. Liu, SCSU

What is file? File - a collection of related records. e.g. Employees in the same department of a company 9/19/2018 ILS 501 / Dr. Liu, SCSU

Database Management System DBMS is a software system that enables users to define, create, and maintain the database and provides controlled access to this database. As a software manager, the software controls the structure of a database and access to the data 9/19/2018 ILS 501 / Dr. Liu, SCSU

Database Management System A DBMS is a data storage and retrieval system which permits data to be stored non-redundantly while making it appear to the user as if the data is well-integrated. 9/19/2018 ILS 501 / Dr. Liu, SCSU

Database Management System DBMS Database containing centralized shared data Application #1 #2 #3 DBMS manages data resources like an operating system manages hardware resources 9/19/2018 ILS 501 / Dr. Liu, SCSU

Advantages of Database Approach Program-Data Independence Metadata stored in DBMS, so applications don’t need to worry about data formats Data queries/updates managed by DBMS so programs don’t need to process data access routines Results in: increased application development and maintenance productivity Minimal Data Redundancy Leads to increased data integrity/consistency 9/19/2018 ILS 501 / Dr. Liu, SCSU

Advantages of Database Approach Improved Data Sharing Different users get different views of the data Enforcement of Standards All data access is done in the same way Improved Data Quality Constraints, data validation rules Better Data Accessibility/ Responsiveness Use of standard data query language (SQL) Security, Backup/Recovery, Concurrency Disaster recovery is easier 9/19/2018 ILS 501 / Dr. Liu, SCSU

What does DBMS do? Enables you to store, modify, and extract information from a database. It can reduce data redundancy improve data integrity increase user productivity increase security 9/19/2018 ILS 501 / Dr. Liu, SCSU

Four common databases Hierarchical database Network database Relational database Object-oriented database 9/19/2018 ILS 501 / Dr. Liu, SCSU

Four common databases- Hierarchical database A hierarchic data structure consists of a family or ordered set of trees. Data records in this system have a child-parent relationship - a child record has exactly one parent. It is not flexible for adding new fields. 9/19/2018 ILS 501 / Dr. Liu, SCSU

Example of cruise ship reservation system Hierarchical database - fields or records are arranged in related groups, resembling a family tree, with child (lower-level) records subordinate to parent (higher-level) records The hierarchical database is the oldest and simplest of the four models. It is quite rigid because the structure must be defined in advance. The figure illustrates hierarchical database with an example of a cruise ship reservation system. Example of cruise ship reservation system 9/19/2018 ILS 501 / Dr. Liu, SCSU

Four common databases- Network database A network data structure can be regarded as an extended form of the hierarchic data structure, a child record can have any number of parents. It maps out relationships between member records and owner records, such as scheduling system. 9/19/2018 ILS 501 / Dr. Liu, SCSU

Example of college class-scheduling system Network database - similar to a hierarchical database, but each child record can have more than one parent record Child record is called a member and may be reached through more than one parent, which is called an owner. Network database is more flexible than the hierarchical arrangement. It still requires that the structure be defined in advance. There are limits to the number of possible links among records. Example of college class-scheduling system 9/19/2018 ILS 501 / Dr. Liu, SCSU

Four common databases- Relational database The relational model is the most popular and flexible data model. Data in it can be stored/accessed through a key field, a common piece of data. It is often used for metadata storage and synchronization control, such as the motor vehicles database-storing account & transaction information Another example: a thesaurus 9/19/2018 ILS 501 / Dr. Liu, SCSU

Example of state department of motor vehicles database Relational database - relates (connects) data in different files through the use of a key field, or common data element Data elements are stored in different tables made up of rows and columns. The tables are called relations (files), the rows are called tuples (records), and the columns are called attributes (fields). FACTOID: SQL (Structured Query Language) - the standard language used to create, modify, maintain, and query relational databases. SQL is pronounced as “sequel.” How did this acronym get such an unlikely pronunciation? The first structured query language was developed by IBM in the 1970s; its product name was “Sequel2.” FACTOID: QBE (Query by example) - feature of most query languages in which the user asks for information in a database by using a sample record to define the qualifications he or she wants for selected records. FACTOID: E. F. Codd is considered the “father” of relational database management systems—the most common model of databases. His article entitled “A Relational Model of Data for Large Shared Data Banks” was published in the June 1970 “Communications of the ACM.” Example of state department of motor vehicles database 9/19/2018 ILS 501 / Dr. Liu, SCSU

Four common databases- Object-oriented database It uses objects as elements within database files. Any type of data can be handled including not only simple data but also image, graphics, and audio/video data. A practical application of this types of database is a Map collection. Example: Facebook, YouTube, MySpace, LibraryThing A relational database uses a key field, object-oriented can find based on images or words 9/19/2018 ILS 501 / Dr. Liu, SCSU

Bibliographic Databases CONSULS http://www.consuls.org/ MadCat http://madcat.library.wisc.edu/ iConn is also an example. 9/19/2018 ILS 501 / Dr. Liu, SCSU

Questions? Thank You 9/19/2018 ILS 501 / Dr. Liu, SCSU