Re: Convert an SQL insert into a Perl data structure

Maybe a case of tl;dr but you are aware of the possibilities to (meta) query the MySQL schemas as such, without needing to parse the CREATE statements with regex? °

IIRC was DBI.pm also (additionally) offering methods for this

Edit

See meta query MySQL for examples

°) E.G. look out for the DB/Schema INFORMATION_SCHEMA inside MySQL, but IIRC TIMTOWTDI.

Cheers Rolf
_{(addicted to the 𐍀𐌴𐍂𐌻 Programming Language :)

Wikisyntax for the Monastery}

Comment on Re: Convert an SQL insert into a Perl data structure

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Re^2: Convert an SQL insert into a Perl data structure by bliako (Abbot) on Apr 05, 2023 at 11:57 UTC
Hmm, at first I thought that's a great idea. But then reality hit: in this way, I would need somehow to juggle two different database versions existing at the same time while I read data from the old DB (ODB), process it and add it to the new DB (NDB). I guess I would need to rename one database and that could blow. Whereas what my situation is: ODB exists and is running. An update is coming and a NDB must be created based on ODB's data plus some added columns for certain tables. I dump the ODB to file. I erase ODB. I create NDB with no data. I read the ODB's dumpfile, process it (to add some values for the new columns) and insert it into NDB. So, perhaps I can exploit your idea by creating my version of `mysqldump` based on DBI which is friendlier to my aims. Earlier answer: Yep, that's a good way: SHOW COLUMNS and then ask DBI to SELECT and get back all results as Perl data structure. Actually no need for SHOW COLUMNS, just a SELECT will contain a hash with column names/values. After your suggestion I saw DBI, add fields to existing table? which shows how to add columns with ALTER TABLE. bw, bliako	[reply] [d/l]

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Re^2: Convert an SQL insert into a Perl data structure
by bliako (Abbot) on Apr 05, 2023 at 11:57 UTC

Hmm, at first I thought that's a great idea. But then reality hit: in this way, I would need somehow to juggle two different database versions existing at the same time while I read data from the old DB (ODB), process it and add it to the new DB (NDB). I guess I would need to rename one database and that could blow.

Whereas what my situation is: ODB exists and is running. An update is coming and a NDB must be created based on ODB's data plus some added columns for certain tables. I dump the ODB to file. I erase ODB. I create NDB with no data. I read the ODB's dumpfile, process it (to add some values for the new columns) and insert it into NDB.

So, perhaps I can exploit your idea by creating my version of mysqldump based on DBI which is friendlier to my aims.

Earlier answer: Yep, that's a good way: SHOW COLUMNS and then ask DBI to SELECT and get back all results as Perl data structure. Actually no need for SHOW COLUMNS, just a SELECT will contain a hash with column names/values. After your suggestion I saw DBI, add fields to existing table? which shows how to add columns with ALTER TABLE.

bw, bliako

[reply]
[d/l]