Re: [Haskell-cafe] Haskell SQL backends: How is data handed over?
the backend constructs a complete SQL query statement in form of a string (including the SqlValues), and hands that to the database driver to parse. Is that indeed so?
Hi Olaf, that's the usual format for any HLL to pass statements (queries or updates) to SQL. Most HLLs provide some sort of modulate/demodulate so your program doesn't see the raw numbers-as-strings, but the parsing is going on in the background. Going via CSV isn't really saving anything: the "bulk insert" is again parsing those commas and the bits in between. (A dedicated SQL engine is probably more efficient than Haskell's string handling.) AntC
More specifically, a query or DML statement is a string with ?
placeholders for values, which is "prepare"d to turn it into internal
format and then executed one or more times with values supplied.
On Tue, Aug 9, 2022 at 4:51 PM Anthony Clayden
the backend constructs a complete SQL query statement in form of a string (including the SqlValues), and hands that to the database driver to parse. Is that indeed so?
Hi Olaf, that's the usual format for any HLL to pass statements (queries or updates) to SQL.
Most HLLs provide some sort of modulate/demodulate so your program doesn't see the raw numbers-as-strings, but the parsing is going on in the background.
Going via CSV isn't really saving anything: the "bulk insert" is again parsing those commas and the bits in between. (A dedicated SQL engine is probably more efficient than Haskell's string handling.)
AntC _______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.
-- brandon s allbery kf8nh allbery.b@gmail.com
On Tue, Aug 09, 2022 at 04:53:58PM -0400, Brandon Allbery wrote:
More specifically, a query or DML statement is a string with ? placeholders for values, which is "prepare"d to turn it into internal format and then executed one or more times with values supplied.
The values are serialised, but typically not as strings, avoiding both a performance penalty and potential SQL-injection issues. -- Viktor.
participants (3)
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Anthony Clayden -
Brandon Allbery -
Viktor Dukhovni