final_review

final_review - CSC101 Final Review Sheets Chapter 11 Study...

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CSC101 Final Review Sheets Chapter 11 Study Guide Data used to be stored on magnetic tape Sequential storage o Data is stored and retrieved in sequence o Less expensive o Searching is SLOW o Examples : Floppy disk Magnetic Tape Direct access storage o the computer can go directly to the information desired o Data retrieved using KEY o Uses File Allocation Table (FAT) o More expensive and complex o Searching is FAST o Examples : Hard Disk CD-ROM DVD What is a database? o Electronic collection of related data o Helps us organize data o Makes it easy to access data for use When is a database needed? o You need a database o Any time complex information needs to organize or if more than one person needs to access it. o For example, When you enrolled in college you provided information about yourself (name, address, classes selections) The school also keeps track of what dorm your in and how much money you have on your gull card. Database Management Systems o DBMS - programs that control the structure of a database and access to the data o Advantages of a DBMS Provide data centralization Reduced data redundancy
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CSC101 Final Review Sheets Don’t need to repeat the same information over and over Increased security Information can be limited to select users. Ease of data maintenance There are procedures for adding, deleting and modifying records. Backup utilities Validation Checks o Application software designed to capture and analyze data o Four main operations of a DBMS are: Creating databases and entering data Viewing and sorting data Extracting data Outputting data Advantages of using Databases: o Store and retrieve large quantities of information o Improved data integrity o Data is accurate, consistent and up to date! o Enable information sharing o Allow for flexible use of data Database Terminology o Field Category of information displayed in columns Each field has a field name o Data types Text Numeric Computational Date Memo Object Hyperlink o Record A group of related fields o Table A group of related records o Primary key A field value unique to a record Different forms of data o Numbers Mathematical values
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CSC101 Final Review Sheets Use with Mathematical Functions ( +, -, *, / ) Integers or Whole numbers 0, 1, 350, 2000, 1000000 Real Numbers or Floating Point 0.0, 5.0, 3.1418, 89.25, 1000.12345 o Alphanumeric Characters Letters, numbers, punctuation marks ASCII Code represents each character We can’t perform mathematical function with these numbers. They are just text! 1600 Pennsylvania Avenue
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final_review - CSC101 Final Review Sheets Chapter 11 Study...

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