Introduction to Databases A line manager asks, “If data unorganized is like matter unorganized and God created the heavens and earth in six days, how come it takes six months for all these consultants to build a database model for a simple business process?”

Introduction to Databases File System Limitations File System Limitations Database Systems Database Systems History of Databases History of Databases Pros & Cons of Databases Pros & Cons of Databases Database Careers Database Careers

File System Limitations Section #1 Separating and Joining Data Separating and Joining Data Duplicating Data Duplicating Data Data Dependence Data Dependence Incompatible File Formats Incompatible File Formats Fixed Queries Fixed Queries Security Limitations Security Limitations

Separating and Isolating Data Files store related data about a subject Files store related data about a subject Files only contain information for their primary purpose. Files only contain information for their primary purpose. Joining files lets you answer questions Joining files lets you answer questions Programs resolve complex relationships and formatting between different files. Programs resolve complex relationships and formatting between different files. Business reports read multiple files Business reports read multiple files Programmers write reports by joining data from multiple files to create meaningful information. Programmers write reports by joining data from multiple files to create meaningful information.

Duplicatiing Data Files systems duplicate data Files systems duplicate data Files become data islands with complex organization, and store copies of secondary data from other files. Files become data islands with complex organization, and store copies of secondary data from other files. Files maintain their copy of the data Files maintain their copy of the data Files maintain their own copy of data and change the data without advising the primary source file. Files maintain their own copy of data and change the data without advising the primary source file. Duplicate data leads to inconsistent data Duplicate data leads to inconsistent data Over time, businesses don’t know which file contains the most accurate data, and can make bad decisions. Over time, businesses don’t know which file contains the most accurate data, and can make bad decisions.

Data Dependence Physical storage in files Physical storage in files Files store things in structures or lines of text and they are called flat files. Files store things in structures or lines of text and they are called flat files. Delimiters, parsing and concatenating Delimiters, parsing and concatenating Delimiters are non-text characters separating data elements, and can be XML tags. Delimiters are non-text characters separating data elements, and can be XML tags. Position specific files Position specific files Files organized by physical position define what character range contains a data element. Files organized by physical position define what character range contains a data element.

Incompatible File Formats Programming languages differ Programming languages differ Files written by C/C++ differ from files written by COBOL or RPG. Files written by C/C++ differ from files written by COBOL or RPG. Programmers solve problems differently Programmers solve problems differently Organization of files differs dependent on how the programmer saw the problem. Organization of files differs dependent on how the programmer saw the problem. Formats differ Formats differ Data structures differ between files and require mapping their differences. Data structures differ between files and require mapping their differences.

Fixed Queries Fixed queries report or enter data Fixed queries report or enter data These are programs dealing with one or more files that are reports or data entry forms. These are programs dealing with one or more files that are reports or data entry forms. Fixed queries are written by programmers Fixed queries are written by programmers Programmers write reports and forms as requested and budgeted by organizations. Programmers write reports and forms as requested and budgeted by organizations. Fixed queries don’t answer Ad Hoc questions Fixed queries don’t answer Ad Hoc questions Impromptu end-user questions can’t be answered without the assistance of an IT organization. Impromptu end-user questions can’t be answered without the assistance of an IT organization.

Security Limitations File ownership limits File ownership limits Primary source files are controlled by one organization in businesses. Primary source files are controlled by one organization in businesses. File change limits File change limits Primary source files are changeable only with permission of the owning organization. Primary source files are changeable only with permission of the owning organization. File confidentiality File confidentiality Primary source files are viewable as a whole and cannot be restricted by data elements, resulting in compromised confidentiality. Primary source files are viewable as a whole and cannot be restricted by data elements, resulting in compromised confidentiality.

File System Limitations Review Section #1 Separating and Joining Data Separating and Joining Data Duplicating Data Duplicating Data Data Dependence Data Dependence Incompatible File Formats Incompatible File Formats Fixed Queries Fixed Queries Security Limitations Security Limitations

Database Systems Section #2 Database Instance Database Instance Database Management System Database Management System Standard Language Interface Standard Language Interface Security Privileges & Roles Security Privileges & Roles Database Types Database Types

Database Instance Data and the definition of data are stored in an organized way. Data and the definition of data are stored in an organized way. Data is stored in tables that are 2D arrays, like a spreadsheet. Data is stored in tables that are 2D arrays, like a spreadsheet. Data definition is metadata, or data about data, which is also stored in tables. Data definition is metadata, or data about data, which is also stored in tables. Data can also contain stored programs that let you access data. Data can also contain stored programs that let you access data.

Database Management System Programs that manage and access the database instance. Programs that manage and access the database instance. Programs that let external programs access the database instance. Programs that let external programs access the database instance. Programs that control access to the database instance. Programs that control access to the database instance. Programs that backup and recover the database instance. Programs that backup and recover the database instance.

Standard Language Interface Structured Query Language (SQL) Structured Query Language (SQL) Structured English QUEry Language (SEQUEL) Structured English QUEry Language (SEQUEL) ANSI Standards ANSI Standards ANSI SQL-86 ANSI SQL-86 ANSI SQL-89 ANSI SQL-89 ANSI SQL-92 ANSI SQL-92 ANSI SQL:1999 ANSI SQL:1999 ANSI SQL:2003 ANSI SQL:2003

Security Privileges & Roles Security is tiered by ANSI-SPARC rules Security is tiered by ANSI-SPARC rules Superuser – holds internal data Superuser – holds internal data Administrator – holds conceptual data Administrator – holds conceptual data User – holds external data User – holds external data Superuser grants privileges to users Superuser grants privileges to users Grants individual privileges one at a time. Grants individual privileges one at a time. Creates roles as groups of privileges. Creates roles as groups of privileges. Grants grouped privileges as roles. Grants grouped privileges as roles. Data can be restricted at various levels Data can be restricted at various levels

Database Types Database types Database types Operational – dynamic, time-independent, and critical business operational data. Operational – dynamic, time-independent, and critical business operational data. Analytical – statistical, historic, and time-dependent business data. Analytical – statistical, historic, and time-dependent business data. Database implementation types Database implementation types Online Transactional Processing (OLTP) – business applications, also known as operational databases. Online Transactional Processing (OLTP) – business applications, also known as operational databases. Online Analytical Processing (OLAP) – data warehouses, also known as analytical databases. Online Analytical Processing (OLAP) – data warehouses, also known as analytical databases.

Database Systems Revised Section #2 Database Instance Database Instance Database Management System Database Management System Standard Language Interface Standard Language Interface Security Privileges & Roles Security Privileges & Roles Database Types Database Types

History of Databases Section #3 File Systems File Systems Hierarchical File Systems Hierarchical File Systems Networked File Systems Networked File Systems Relational Databases Relational Databases Object Relational Databases Object Relational Databases Also known as Extended Relational Databases Also known as Extended Relational Databases Object-Oriented Databases Object-Oriented Databases

File Systems Files were the first way to organize data. Files were the first way to organize data. Files contain related data in structures. Files contain related data in structures. File systems contain files, and they duplicate and corrupt copies of data. File systems contain files, and they duplicate and corrupt copies of data. File systems are programming language specific, restricting file sharing. File systems are programming language specific, restricting file sharing. File systems have too many structures. File systems have too many structures.

Hierarchical File Systems Are defined by an inverted tree Are defined by an inverted tree The top most node is a parent, who can have child nodes, and the bottom node is a leaf node – by a parent-child pointer. The top most node is a parent, who can have child nodes, and the bottom node is a leaf node – by a parent-child pointer. You navigate from the top most node to all subordinate nodes, which becomes expensive when data is spread out. You navigate from the top most node to all subordinate nodes, which becomes expensive when data is spread out.

Networked File Systems Are also defined by an inverted tree Are also defined by an inverted tree The top most node (also a set structure) links by a pointer or list of pointers to other set structures or nodes. The top most node (also a set structure) links by a pointer or list of pointers to other set structures or nodes. Searches are made from node to node through pointers that associate a node with subordinate nodes or set structure. Searches are made from node to node through pointers that associate a node with subordinate nodes or set structure.

Relational Databases Are defined by tables. Are defined by tables. Tables are defined by a list of columns, known as a signature. Tables are defined by a list of columns, known as a signature. Metadata tables hold definitions of tables. Metadata tables hold definitions of tables. Links between tables are dynamic relationships as opposed to stored pointer structures. Links between tables are dynamic relationships as opposed to stored pointer structures. Relationships between tables are made by comparing values in columns, and columns are known as primary and foreign keys. Relationships between tables are made by comparing values in columns, and columns are known as primary and foreign keys.

Object Relational Databases (Extended Relational Databases) Are defined by objects, which can be tables, nested collections, or objects with methods. Are defined by objects, which can be tables, nested collections, or objects with methods. Objects are defined by a list of columns, known as a signature, which can contain methods. Objects are defined by a list of columns, known as a signature, which can contain methods. Metadata tables hold definitions of objects. Metadata tables hold definitions of objects. Links between objects are dynamic relationships. Links between objects are dynamic relationships. Relationships between objects are made by comparing values in columns, and columns are known as primary and foreign keys. Relationships between objects are made by comparing values in columns, and columns are known as primary and foreign keys.

Object-Oriented Databases Are defined by instantiable objects with methods. Are defined by instantiable objects with methods. Objects are defined by a list of attributes with a constructor and methods. Objects are defined by a list of attributes with a constructor and methods. Metadata tables hold definitions of objects. Metadata tables hold definitions of objects. Links between objects are dynamic relationships. Links between objects are dynamic relationships. Relationships between objects are made during instantiation of object instances by dynamic marshalling. Relationships between objects are made during instantiation of object instances by dynamic marshalling.

History of Databases Review Section #3 File Systems File Systems Hierarchical File Systems Hierarchical File Systems Networked File Systems Networked File Systems Relational Databases Relational Databases Object Relational Databases Object Relational Databases Also known as Extended Relational Databases Also known as Extended Relational Databases Object-Oriented Databases Object-Oriented Databases

Pros & Cons of Databases Section #4 Advantages Advantages Data redundancy control, consistency, sharing, integrity, security, access, responsiveness, concurrency, independence, and backup/recovery. Data redundancy control, consistency, sharing, integrity, security, access, responsiveness, concurrency, independence, and backup/recovery. Disadvantages Disadvantages Complexity, conversion costs, performance, and all-or-nothing risk of catastrophic failure. Complexity, conversion costs, performance, and all-or-nothing risk of catastrophic failure.

Database Careers Section #5 Database Administrator (DBA) Database Administrator (DBA) Physical Database Administrator Physical Database Administrator Application Database Administrator Application Database Administrator Database Analyst Database Analyst Database Designer Database Designer Database Programmer Database Programmer

Database Administrator (DBA) Physical Database Administrator Physical Database Administrator Physical file administration and ownership Physical file administration and ownership Startup and shutdown authority Startup and shutdown authority Backup and recovery responsibility Backup and recovery responsibility Application Database Administrator Application Database Administrator Privilege and role administration Privilege and role administration User/schema administration User/schema administration Operations and tuning administration Operations and tuning administration

Database Analyst Database physical model implementation Database physical model implementation Translation of logical design to physical model Translation of logical design to physical model Analysis of query performance Analysis of query performance Analysis of index performance Analysis of index performance Database data integrity Database data integrity Analysis of insertion, update and deletion anomalies Analysis of insertion, update and deletion anomalies Analysis of primary and foreign key validation Analysis of primary and foreign key validation

Database Designer Define a data model for business process Define a data model for business process Meet with users and define requirements Meet with users and define requirements Understand the purpose of the business Understand the purpose of the business Design a logical model to manage data Design a logical model to manage data Define primary and foreign key relationships Define primary and foreign key relationships Render model and generate build scripts Render model and generate build scripts Secure business acceptance of model Secure business acceptance of model

Database Programmer Define a business processes Define a business processes Meet with users and define requirements Meet with users and define requirements Understand the purpose of the business Understand the purpose of the business Design a program architecture for process Design a program architecture for process Write programs to support process Write programs to support process Coordinate unit and integration testing Coordinate unit and integration testing Document and release code to production Document and release code to production

Database Careers Review Section #5 Database Administrator (DBA) Database Administrator (DBA) Physical Database Administrator Physical Database Administrator Application Database Administrator Application Database Administrator Database Analyst Database Analyst Database Designer Database Designer Database Programmer Database Programmer

Summary File System Limitations File System Limitations Database Systems Database Systems History of Databases History of Databases Pros & Cons of Databases Pros & Cons of Databases Database Careers Database Careers