Convenience exec/query overloads that do parameterized SQL

[Abscissa]

...using prepared statements behind-the scenes.

Ie:

conn.query("SELECT * FROM mytable WHERE id=? AND name=?", 7, "Frank")

[schveiguy]

One other simple possibility is to expand the query and exec methods of PreparedImpl to allow one-line execution of sequences.

For example:

auto prep = conn.prepare("SELECT * FROM mytable WHERE id=? AND name=?");
foreach(r; prep.query(7, "Frank")) { ... }

If you do go for the one liner, one thing that the current implementation makes a bit cumbersome is that you have to store the Prepared somewhere while you iterate, or it will try to purge the result and release the prepared statement (this is how I came across #117). The way I solved it is to create a wrapper struct that holds both the Prepared struct and the ResultRange, and I alias this the range. Of course, if you mitigate that in ways that we discussed in that issue, it may make things much nicer.

[quickfur]

FWIW, in my NIH version of sqlite.d, I just use RefCounted on the prepared statement (which in turn holds a reference to a RefCounted database handle) so that I don't have to worry about keeping track of who's referencing what, where, and when they will be done. I just let the refcounting do its job. :-P

[Abscissa]

FWIW, The refcoutning problem @schveiguy refers to above was fixed in v1.1.4 (see second-to-last bullet item under v1.4.4)

[Abscissa]

Added in branch "v2.1.x" via 7a8fc46, e793af7, and 35cddc8

[schveiguy]

Nice. I may be able to just about eliminate my templates that do this :)

[schveiguy]

I have to come back here to say, was able to trim out ALL of my cruft in my DB wrapper. Things in mysql-native are looking awesome!

• I no longer need Refcounted wrapper structs
• I no longer need these convenience wrappers (I simply had to rename my fetch calls to query, and things worked seamlessly, and I had already named my non-data-returning function exec, so no changes needed there).
• I no longer have extra scopes to ensure ref counting does the "right thing". Things just work.

I was able to delete probably about 130 lines of code from my project that just dealt with wrapping and lifetime. Kudos!

[Abscissa]

Glad to hear it!