Topic 6 - Databases
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Database
A persistent structured collection of data that allows people to extract information in a way that meets their needs
Single-table database
A database that contains only one table
Table
A collection of related records in a database
Record (2)
• rows • collection of fields that describe one item
Field (2)
• column • database table
Data type
A classification of how data is stored and displayed, and of which operations that can be performed on the stored value
Primary key
A field in a database that uniquely identifies record
SELECT
Fetches specific fields (columns) from a table
FROM
Command that identifies the table to use
WHERE
command t include only those records (rows) in a query that match a given condition
ORDER BY (ASC/DESC)
A command that sorts the results from a query by a given column either alphabetically or numerically
SUM
A command that returns the sum of all the values in a field (column) used with select
COUNT
A command that counts the number of records (rows) in which the field (column) matches the specified condition, used with SELECT