On 12/21/07, Mathieu Bouchard matju@artengine.ca wrote:
On Tue, 18 Dec 2007, Mike McGonagle wrote:
[query <srv_id> insert into mytable (id, name, token) values
(?f,'?s','?s')]
In this example, the first placeholder would expect a Float, with the
next
two expecting a Symbol (just think of this as a variation on the printf string substitutions).
It looks more like the types of [t] [pack] [unpack] [expr] etc.
Yes, they are PD types.
You don't really need to type your data. SQL is largely typeless: at least
at the level of what you can put in one table cell, anything is a string. It becomes typed (but auto-cast) when put in the cell, but rebecomes untyped when taken out of the cell.
Yes, I know that these things can be stored in a typeless manner, but the functions that bind the SQL statement with their placeholders can be of any type, as there are functions for the various datatypes.
http://www.sqlite.org/c3ref/bind_blob.html
This link shows all the different functions used to bind the data to the statement placeholders.
http://dev.mysql.com/doc/refman/5.0/en/c-api-prepared-statement-datatypes.ht...
And if you look at how MySQL does this, while they only provide a single bind function, it does have the datatypes for the data in a structure that gets passed into the bind function.
Also, from looking at libdbi, it appears that they don't even bother with placeholders at all.
This is not an issue of how the user sees these things, it is how the C code interfaces with the database.
So, just how do we do this in a consistent manner when all the different interfaces don't support these things, AND if they do, they do them differently.
but considering that the databases need to know the specific data types
for each placeholder,
heh? do they?
SQLite does. MySQL appears to as well. And yes, it is possible to just force everything to be a string/c-string and be done with it. SQLite actually stores everything as a string anyway, despite the defined types in the create statement.
Mike
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