1. Fields
One feature of a thing
2. Record
A combination of fields, is represented by a specific thing
3. Table
Combined record of representing a collection of the same type of thing
4. Relationship between fields, records, tables
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Field is a property of things
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Record is the thing itself
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Table is a collection of things
5. Column
Table set of a certain feature of all things
6. Line
Another title record
7. Properties
Another title field
8. tuple
Another title record
9. Primary Key
definition:
The only thing can be a combination of a label field or multiple fields, referred to as the primary key
Features:
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Table containing the primary key is called the primary table
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The value of the primary key are usually not allowed to modify, except where the record is deleted
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Use surrogate primary key, do not use natural key
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Any one table, there are strongly discouraged business meaning of the act as the primary key field
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We usually add a separate integer numbers in the table serves as a primary key field
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If the primary key is not very important to the continuous growth
10. A foreign key
definition:
If the primary key or a unique key in the table is the number of fields from another table number, then this number is a foreign key field
note:
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Typically primary key the foreign key from another table, rather than a unique key, because the unique key may be null
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Table containing the foreign key is called from the table, a table that is called a foreign key field from the main table