ENV100H1 Lecture Notes - Lecture 8: Unstructured Data, Computer Language, Query Language
16 Jan 2018
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Document Summary
Database: collection of related data that can be stored, sorted, organized, and queried. Eg. using an atm,shopping online, making an airplane reservation. Created and managed using a database management system (dbms) 4 main operations: creating databases and entering data, viewing or browsing and sorting data, querying/extracting data, outputting data. Databases are not essential for simple lists lists can lead to inefficiencies due to repetition of data and errors. Data redundancy: data entered multiple times and on different lists. Data inconsistency: different data on different lists. Accurate and reliable time consuming & expensive to set up and administer. Metadata: data that describes other data field name. Distinguishes what data can be stored in the field. Primary key field: a unique value to each record. Normalization: the process to ensure data id organizes more efficiently. Eg. same first and last names but unique student id #s. Operate by organizing data into various tables. Relationship: a common field to link between 2 tables.
