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Some database implementations adopted the term upsert (a portmanteau of update and insert) to a database statement, or combination of statements, that inserts a record to a table in a database if the record does not exist or, if the record already exists, updates the existing record. This synonym is used in PostgreSQL (v9.5+) [2] and SQLite (v3 ...
Tables normally include a hidden rowid index column, which provides faster access. [30] If a table includes an INTEGER PRIMARY KEY column, SQLite will typically optimize it by treating it as an alias for the rowid, causing the contents to be stored as a strictly typed 64-bit signed integer and changing its behavior to be somewhat like an auto ...
For example, a database that represents company contact information might have the following columns: ID, Company Name, Address Line 1, Address Line 2, City, and Postal Code. More formally, a row is a tuple containing a specific value for each column, [ 4 ] for example: (1234, 'Big Company Inc.', '123 East Example Street', '456 West Example ...
The primary keys within a database are used to define the relationships among the tables. When a PK migrates to another table, it becomes a foreign key (FK) in the other table. When each cell can contain only one value and the PK migrates into a regular entity table, this design pattern can represent either a one-to-one or one-to-many relationship.
Access tables support a variety of standard field types, indices, and referential integrity including cascading updates and deletes. Access also includes a query interface, forms to display and enter data, and reports for printing. The underlying Access database, which contains these objects, is multi-user and handles record-locking.
When the data model is instantiated into a physical database, it is the key that the system uses the most when accessing the table, or joining the tables together when selecting data. Alternate A non-primary key that can be used to identify only one row in a table. Alternate keys may be used like a primary key in a single-table select. Foreign
This work has been released into the public domain by its author, D. Richard Hipp.This applies worldwide. In some countries this may not be legally possible; if so: D. Richard Hipp grants anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.
A web page from Wikipedia displayed in Google Chrome. The World Wide Web (WWW or simply the Web) is an information system that enables content sharing over the Internet through user-friendly ways meant to appeal to users beyond IT specialists and hobbyists. [1]