Data stored in the database is faster than the data file, such as XML to take relatively fast

Data stored in the database is faster or more data files such as XML in the faster
I do the provinces and cities linkage, the data is not changed, is placed in the database in a relatively fast or in a data file similar to XML to take a relatively fast value? Please help the experts to answer the question
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This data is not changed in PHP configuration can be

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In the memory type of the database, the data is not changed, directly with the static JSON data, without parsing.
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Make standalone JS file the fastest (available in browser cache)
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So you think the transfer of a ready-made JS file and generate a JS file the same data and transmission, that will be faster?

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