Mapa mental
Databases
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Databases
Each column is called a field and each row is called a record.
FIELDS will have DATA TYPES. For example Name will be TEXT DATA TYPE. Primary Key will be AUTONUMBER DATA TYPE.
Database is a system for managing a collection of data. Data about a particular type of thing – for example, customers or products – is stored in a table . You can think of a table as a grid. Every row in the table holds information about a single item; this is also called a record . Every column holds information about a property of the items in the table, such as a customer’s name or an item’s price – these properties are called fi elds .
Text (also called characters or strings ): sequences of letters, numbers and other symbols. Someone’s name would be a text field. A field that can accept multi-line text is often called a memo field.
Number: represents a numerical value. A product’s price or the number of items left in stock would be stored as numbers. This would enable you to produce a report summing up the prices of all the products you had sold, which wouldn’t be possible if they were stored as text.
Date/time: stores dates or a combination of dates and times.
Logical (also called Boolean or Yes/no ): represents a value that is either true or false. For example, when a customer opens an account with an online company, they might be asked whether they are happy to receive marketing material. Their answer could be stored in a logical fi eld (true if they are happy to receive marketing information, false if they are not).
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- Mapa Mental sobre Databases, creado por ow28058 el 16/10/2015.
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- ow28058
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