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AWS account associated with a particular developer.
Similar to columns on a spreadsheet, attributes represent categories of data that can be assigned to items.
All Amazon SimpleDB information is stored in domains. Domains are similar to tables that contain similar data. You can execute queries against a domain, but cannot execute joins between domains.
A customer can have up to 100 domains at any time. The name of the domain must be unique within the customer account.
Amazon SimpleDB keeps multiple copies of each domain. When data is written or updated (using PutAttributes, DeleteAttributes, CreateDomain or DeleteDomain) and "Success" is returned, all copies of the data are updated. However, it takes time for the data to propagate to all storage locations. The data will eventually be consistent, but an immediate read might not show the change.
Consistency is usually reached within seconds, but a high system load or network partition might increase this time. Performing a read after a short period of time should return the updated data.
A strategy for reducing the load on the system and increasing the likelihood of repeated requests succeeding by incrementally decreasing the rate at which retries are executed. For example, client applications might wait 400 milliseconds before attempting the first retry, 1600 milliseconds before the second, 6400 milliseconds (6.4 seconds) before the third, and so on.
Similar to rows on a spreadsheet, items represent individual objects that contain one or more value-attribute pairs
An identifier for an item. The identifier must be unique within the domain.
Charges based on the amount of machine capacity used to complete the particular request (QUERY, GET, PUT, etc.), normalized to the hourly capacity of a 1.7 GHz Xeon processor. Machine Utilization is measured in Machine Hour increments.
An attribute with more than one value.
A rare error condition where some Amazon SimpleDB computers cannot contact each other, but all other components are operating correctly. Normally this is repaired within seconds or minutes.
An attribute with one value.
Similar to cells on a spreadsheet, values represent instances of attributes for an item. An attribute might have multiple values.
