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digitalmars.D - RFC - mysqlD

reply Steve Teale <steve.teale britseyeview.com> writes:
I've put some still very rough generated documentation on my web page

http://britseyeview.com/software/mysqld.html

There is probably some MySQL specific stuff still in there, but I think this
is close to being an interface that could be implemented for other database C
api's, and for ODBC.

I'd appreciate some quick comments to find out if I am way off the mark, or if
it is worth pursuing.

Thanks Steve
Oct 02 2011
next sibling parent reply "Vladimir Panteleev" <vladimir thecybershadow.net> writes:
On Sun, 02 Oct 2011 19:52:50 +0300, Steve Teale  
<steve.teale britseyeview.com> wrote:

 I've put some still very rough generated documentation on my web page

 http://britseyeview.com/software/mysqld.html

 There is probably some MySQL specific stuff still in there, but I think  
 this
 is close to being an interface that could be implemented for other  
 database C
 api's, and for ODBC.

 I'd appreciate some quick comments to find out if I am way off the mark,  
 or if
 it is worth pursuing.

1) There seems to be a lot of MySQL-specific stuff in Connection. I guess that when/if the time comes, it will be separated into an abstract class and a MySQL specialization. 2) Setting parameters seems kinda clumsy. It should be doable with one function call with variadic template parameters. 3) In my opinion, querying the database shouldn't involve heap allocations. I have written an SQLite wrapper (around etc.c.sqlite) for basic functionality: https://github.com/CyberShadow/ae/blob/master/sys/sqlite3.d Perhaps you'll find it useful for some insight towards a common interface. -- Best regards, Vladimir mailto:vladimir thecybershadow.net
Oct 02 2011
next sibling parent Steve Teale <steve.teale britseyeview.com> writes:
Vladimir,

SQLite must have a very clean interface compared to MySQL. Your code is very
terse
and tidy.

You are right about the Connection stuff, and I agree with your approach.

I take your point about the parameters. I have the code to create and bind them,
but that needs to be hidden away.

I don't have a strong opinion on heap allocations.

Thanks Steve
Oct 02 2011
prev sibling parent reply GrahamC <grahamc001uk yahoo.co.uk> writes:
Don't forget that quite a few MySQL data structure members are C long types
which are 64 bit on x86_64.

So if you want code to work on x86_64 as well as x86 it needs a type alias.

For example in st_net these members:

struct st_net
{
    Vio *vio;
    ubyte *buff;
    ubyte *buff_end;
    ubyte *write_pos;
    ubyte *read_pos;
    SOCKET fd;
    uint remain_in_buf;   <<<
    uint length;          <<<
    uint buf_length;      <<<
    uint where_b;         <<<
    uint max_packet;      <<<
    uint max_packet_size; <<<


are 32 bit on x86 and 64 bit on x86_64

Many other MySQL structures and quite a few function arguments have the same
issue.

Of course, not many people seem to be using the compiler for 64 bit code at the
moment.
Oct 09 2011
next sibling parent Jonathan M Davis <jmdavisProg gmx.com> writes:
On Sunday, October 09, 2011 14:35:35 Jonathan M Davis wrote:
 On Sunday, October 09, 2011 19:37:31 GrahamC wrote:
 Don't forget that quite a few MySQL data structure members are C long
 types which are 64 bit on x86_64.
 
 So if you want code to work on x86_64 as well as x86 it needs a type
 alias.
 
 For example in st_net these members:
 
 struct st_net
 {
 
     Vio *vio;
     ubyte *buff;
     ubyte *buff_end;
     ubyte *write_pos;
     ubyte *read_pos;
     SOCKET fd;
     uint remain_in_buf;   <<<
     uint length;          <<<
     uint buf_length;      <<<
     uint where_b;         <<<
     uint max_packet;      <<<
     uint max_packet_size; <<<
 
 are 32 bit on x86 and 64 bit on x86_64
 
 Many other MySQL structures and quite a few function arguments have the
 same issue.
 
 Of course, not many people seem to be using the compiler for 64 bit code
 at the moment.

The C types which may differ between x86 and x86_64 are defined in core.stdc.config.

Though it currently only does so for the integral types. - Jonathan M Davis
Oct 09 2011
prev sibling parent Sean Kelly <sean invisibleduck.org> writes:
On Oct 9, 2011, at 2:42 PM, Jonathan M Davis wrote:

 On Sunday, October 09, 2011 14:35:35 Jonathan M Davis wrote:
 On Sunday, October 09, 2011 19:37:31 GrahamC wrote:
 
 The C types which may differ between x86 and x86_64 are defined in
 core.stdc.config.

Though it currently only does so for the integral types.

Which other standard C types vary between x86 and x86_64?
Oct 09 2011
prev sibling next sibling parent "Vladimir Panteleev" <vladimir thecybershadow.net> writes:
On Sun, 02 Oct 2011 23:29:39 +0300, Vladimir Panteleev  
<vladimir thecybershadow.net> wrote:

 3) In my opinion, querying the database shouldn't involve heap  
 allocations.

Erm... except for numeric values, this is almost impossible, of course - I meant to keep allocations to a minimum. For example, unless Reader preallocates - you can only read one result at a time from a Connection, so why separate the two? -- Best regards, Vladimir mailto:vladimir thecybershadow.net
Oct 02 2011
prev sibling next sibling parent Jonathan M Davis <jmdavisProg gmx.com> writes:
On Sunday, October 09, 2011 19:37:31 GrahamC wrote:
 Don't forget that quite a few MySQL data structure members are C long types
 which are 64 bit on x86_64.
 
 So if you want code to work on x86_64 as well as x86 it needs a type alias.
 
 For example in st_net these members:
 
 struct st_net
 {
     Vio *vio;
     ubyte *buff;
     ubyte *buff_end;
     ubyte *write_pos;
     ubyte *read_pos;
     SOCKET fd;
     uint remain_in_buf;   <<<
     uint length;          <<<
     uint buf_length;      <<<
     uint where_b;         <<<
     uint max_packet;      <<<
     uint max_packet_size; <<<
 
 
 are 32 bit on x86 and 64 bit on x86_64
 
 Many other MySQL structures and quite a few function arguments have the same
 issue.
 
 Of course, not many people seem to be using the compiler for 64 bit code at
 the moment.

The C types which may differ between x86 and x86_64 are defined in core.stdc.config. - Jonathan M Davis
Oct 09 2011
prev sibling next sibling parent Sean Kelly <sean invisibleduck.org> writes:
On Oct 9, 2011, at 12:37 PM, GrahamC wrote:

 Don't forget that quite a few MySQL data structure members are C long =

 which are 64 bit on x86_64.
=20
 So if you want code to work on x86_64 as well as x86 it needs a type =

=20
 For example in st_net these members:
=20
 struct st_net
 {
    Vio *vio;
    ubyte *buff;
    ubyte *buff_end;
    ubyte *write_pos;
    ubyte *read_pos;
    SOCKET fd;
    uint remain_in_buf;   <<<
    uint length;          <<<
    uint buf_length;      <<<
    uint where_b;         <<<
    uint max_packet;      <<<
    uint max_packet_size; <<<
=20
=20
 are 32 bit on x86 and 64 bit on x86_64

So use core.stdc.config.c_long? Or is this type not actually a C long = but rather a typedef that varies in some other way?=
Oct 09 2011
prev sibling parent reply Jonathan M Davis <jmdavisProg gmx.com> writes:
On Sunday, October 09, 2011 16:35:20 Sean Kelly wrote:
 On Oct 9, 2011, at 2:42 PM, Jonathan M Davis wrote:
 On Sunday, October 09, 2011 14:35:35 Jonathan M Davis wrote:
 On Sunday, October 09, 2011 19:37:31 GrahamC wrote:
 
 The C types which may differ between x86 and x86_64 are defined in
 core.stdc.config.

Though it currently only does so for the integral types.

Which other standard C types vary between x86 and x86_64?

On Windows, I don't believe that there's a difference on anything. On Linux, long int, unsigned long int, and long double all differ. I thought that long long int differed too (being 128 bit on 64-bit systems), but trying it now on my 64-bit Linux box, it's 64-bit for both -m32 and -m64, so I guess that it doesn't differ. But regardless, the primary one missing from core.stdc.config is long double. - Jonathan M Davis
Oct 09 2011
parent Mike Wey <mike-wey example.com> writes:
On 10/10/2011 01:46 AM, Jonathan M Davis wrote:
 On Sunday, October 09, 2011 16:35:20 Sean Kelly wrote:
 On Oct 9, 2011, at 2:42 PM, Jonathan M Davis wrote:
 On Sunday, October 09, 2011 14:35:35 Jonathan M Davis wrote:
 On Sunday, October 09, 2011 19:37:31 GrahamC wrote:

 The C types which may differ between x86 and x86_64 are defined in
 core.stdc.config.

Though it currently only does so for the integral types.

Which other standard C types vary between x86 and x86_64?

On Windows, I don't believe that there's a difference on anything. On Linux, long int, unsigned long int, and long double all differ. I thought that long long int differed too (being 128 bit on 64-bit systems), but trying it now on my 64-bit Linux box, it's 64-bit for both -m32 and -m64, so I guess that it doesn't differ. But regardless, the primary one missing from core.stdc.config is long double. - Jonathan M Davis

real is the same size as long double, on both 32 and 64 bits linux. -- Mike Wey
Oct 10 2011