[development] Do not let postgresql hold back great patches
larry at garfieldtech.com
Mon Dec 3 06:49:01 UTC 2007
On Monday 03 December 2007, adrian rossouw wrote:
> On 03 Dec 2007, at 6:38 AM, Larry Garfield wrote:
> > #3 is what I'm pushing for in the D7 database overhaul, within
> > reason. How to
> > abstract everything without making the syntax insane or the
> > performance
> > terrible is what I'm currently trying to wrap my head around. The
> > biggest
> > problem is field type handling, which I want to keep away from module
> > developers but varies greatly depending on the database.
> and the biggest issue here is date / time types.
> it's fscking crazy how different these are between databases.
Actually, that one I think I have a solution for, or the beginnings of one.
In PHP 5, there is the DateTime class to represent a date/time in some
timezone. It's great, but not a proper value object. Writing a value object
around DateTime is easy, however, and I've already done one.
So, each database driver defines internally its own format string to convert a
DateTime/DateValue class into the string format it expects for a date/time
stamp. The database driver then detects the presence of an object as an
argument to a query/prepared statement and formats it to its desired format,
which is then inserted into the query. That works for putting a date/time
value into a query (be it insert, update, delete, or select). For reading, I
believe we can use schema API to check if a field is a timestamp field and
then cast it back to a DateValue object. What the performance implication of
that is, though, I do not know. It may be something that we just have to
swallow if we want real database independence, along with always using an
object to represent a date/time (which I think we should be doing anyway).
As for in-SQL operations on the date value, like MONTH() or YEAR() in MySQL?
If someone has an idea for those that doesn't involve regexing every query I
would dearly love to hear it. :-)
Larry Garfield AIM: LOLG42
larry at garfieldtech.com ICQ: 6817012
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