Re: [sqlite] How to get PRIMARY KEY of newly INSERT INTO record

[Sarah M. Weinberger]

Cool! That worked. The VB6 wrapper has a LastInsertAutoID that I never paid
attention / saw before. I will use the other SQL statement that you
mentioned for the C/C++ stuff. Awesome!

Thanks again :-),

Sarah

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Re: [sqlite] any data access and retrieval engine?

[Sarah]

Hi, John Stanton

I really really appreciate your warm help.
That's great if you can send me the codes of B tree and B+ tree. 
Many thanks in advance.

My requirements for data access are as follows:
-all the data are stored in non-volatile memory instead of volatile memory
-the footprint of the DARE should be better less than 100KB
-when executing, the memory occupation should be better less than 20KB
-no need for relational access, just key-value retrieval is ok
-all the create, insert, update work can be done outside, however, pretty fast 
retrieval is needed

If there is some open-source DARE(as excellent as SQLite) suitable for my 
platform, that will be great.
Orelse, I would try to write a simple one.

Sarah


- Original Message - 
From: "John Stanton" <[EMAIL PROTECTED]>
To: <sqlite-users@sqlite.org>
Sent: Monday, October 23, 2006 5:54 AM
Subject: Re: [sqlite] any data access and retrieval engine?


> Clay Dowling wrote:
>> Sarah wrote:
>> 
>>>Hi,all
>>>
>>>First of all, I want to thank all the guys on this mailing list for their 
>>>warm help.
>>>
>>>After 1 more month of work, I finally make SQLite work on my embedded 
>>>environment. SQLite is really great! Many thanks,Drh.
>>>
>>>But, due to the extremely heavy hardware constraints, I have to give up 
>>>SQLite finally. 
>>>
>>>So I'm trying to find a much simpler data access and retrieval engine. 
>>>
>>>Could anyone give me some help on this issue?(some guidance on how to make a 
>>>DARE or is there any open-source one available?) 
>>>
>>>thanks in advance. 
>> 
>> 
>> The Berkeley DB engine and it's related engines might be suitable for
>> your situation.  They don't give relational access, but they do give
>> fast key=>value retreival and that might be suitable.  The SleepyCat DB
>> engine from SleepyCat Software is probably the best, but for a
>> commercial application the licensing fees mean that you have to be well
>> funded and expect a good return on the product.
>> 
>> Clay Dowling
> Berkely DB is still quite bloated.  What do you require for data access?
> For an embedded system you might find something which matches your
> needs very well and has a tiny footprint.
> 
> I can give you some B* Tree code which is suitable for a high
> performance simple and lightweight embedded application or some AVL tree
> code which would suit a simpler smaller scale memory resident embedded
> data access application.  You would have to adapt it to your
> application, but could expect to get your database access in 20K or less
> of executable image.  Of course you have no SQL.
> 
> -
> To unsubscribe, send email to [EMAIL PROTECTED]
> -
>

[sqlite] any data access and retrieval engine?

[Sarah]

Hi,all

First of all, I want to thank all the guys on this mailing list for their warm 
help.

After 1 more month of work, I finally make SQLite work on my embedded 
environment. SQLite is really great! Many thanks,Drh.

But, due to the extremely heavy hardware constraints, I have to give up SQLite 
finally. 

So I'm trying to find a much simpler data access and retrieval engine. 

Could anyone give me some help on this issue?(some guidance on how to make a 
DARE or is there any open-source one available?) 

thanks in advance. 

[sqlite] Can anyone recommend some ISAM db to me?

[Sarah]

Hi, all
After trying SQLite on my embedded platform, I feel that it's a little too 
complicated and time-consuming to my platform, especially the parsing.
So, could someone recommend several ISAM ones to me?(I'm a newbie of 
database*^_^*)

[sqlite] about temp table

[Sarah]

Hi,all

I met some problem when executing the following test program in an embedded 
environment without os. It seems that temp table isn't created correctly.
   sqlite3_exec(db, "create table myt(age smallint)", NULL, NULL, NULL);

Could someone explain 'the functionality of temp table and when it is created' 
for me? Or give me some links to the web page about temp table.

If I define OMIT_TEMPTABLE, then what's the consequence?

Thanks.

Re: [sqlite] met "ARM7TDMI raised an exception,data abort" when executing sqlite3Parser() in ARM environment

[Sarah]

Hi, 

When you ported sqlite to your os-less ARM based platform, did you do any other 
changes to the sqlite source code?

I'm facing new problems right now. the record cann't be inserted correctly when 
I execute the following statements. 
..
char * database = ":memory:";
 sqlite3 * db;
  sqlite3_open(database, );
  sqlite3_exec(db, "create table myt(name varchar(30),age smallint)", NULL, 
NULL, NULL);
  sqlite3_exec(db, "insert into myt values('sarah',27)", NULL, NULL, NULL);
  sqlite3_exec(db, "select * from myt", NULL, NULL, NULL);
  sqlite3_close(db);
..

The behavior is that , when executing "insert into myt values('sarah',27)",  
the program goes into the following statements in sqlite3RunParser() and 
returns 
SQLITE_NOMEM. How and why? 
..
abort_parse:
  if( zSql[i]==0 && nErr==0 && pParse->rc==SQLITE_OK ){
if( lastTokenParsed!=TK_SEMI ){
  sqlite3Parser(pEngine, TK_SEMI, pParse->sLastToken, pParse);
  pParse->zTail = [i];
}
sqlite3Parser(pEngine, 0, pParse->sLastToken, pParse);
  }
  sqlite3ParserFree(pEngine, sqlite3FreeX);
  if( sqlite3MallocFailed() ){
pParse->rc = SQLITE_NOMEM;
  }
..

I totally have no idea of the principals of parser and how it works. Could 
someone tell me or give me some links?

finally, a stupid question:
should I add a semicolon at the end of the sql statement in sqlite3_exec(); 
Will that affect the execution of parser?

a lot of thanks!



- Original Message - 
From: "Barrass, Richard" <[EMAIL PROTECTED]>
To: <sqlite-users@sqlite.org>
Sent: Tuesday, September 12, 2006 7:41 PM
Subject: RE: [sqlite] met "ARM7TDMI raised an exception,data abort" when 
executing sqlite3Parser() in ARM environment


Hi

We have sqlite (v3.3.7) running on an os-less ARM based platform - we
use MINGW cross compilers (GCC3.4.4) - from CodeSourcery.

There was an issue earlier on that seems to be an issue with 64 bit
support - we switched off the 64bit support in the compilation of the
sqlite library and this for now has got the data base up and running on
our platform.

Richard



-Original Message-
From: Nuno Lucas [mailto:[EMAIL PROTECTED] 
Sent: 11 September 2006 21:12
To: sqlite-users@sqlite.org
Subject: Re: [sqlite] met "ARM7TDMI raised an exception,data abort" when
executing sqlite3Parser() in ARM environment


[forgot to reply to the list]

-- Forwarded message --
From: Nuno Lucas <[EMAIL PROTECTED]>
Date: Sep 11, 2006 9:07 PM
Subject: Re: Re: [sqlite] met "ARM7TDMI raised an exception,data abort"
when executing sqlite3Parser() in ARM environment
To: [EMAIL PROTECTED]


On 9/11/06, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> I don't think NULL callback and error pointer will be the reason. 
> Because I've seen this kind of usage in the list for several times.

As I said earlier, I don't think this is the reason also. Just one more
thing you could check.

> Anyway, I'll try later and report the result to the list.
>
> If it is a misaligned-pointer problem, what can I do?
>
> I don't make any change to the sqlite source code, how should this 
> happen? I can run it correctly on PC(windows XP), why can't in an 
> embedded environment? I'm confused...

You are aware they are completely different architectures, don't you?

You also didn't specify what OS you are running, which could make it
easier to get help from other experienced programmers for your platform
(if you are using CodeWarrior I would guess it's not Windows CE).

A misaligned-pointer can never occur on Windows (desktop editions, not
Windows CE), because Windows only runs on the Intel x86 processor
family, which mask that kind of things from you (although you usually
have a performance hit).

Basically it means you are accessing memory that is not aligned to the
minimum granularity the processor supports (which depends on the
processor and processor mode, but usually is 32 bits - 4 bytes - for
32-bits cpus, 64 bits - 8 bytes - for 64-bits cpus, etc).

I don't know if that is your case, but I have seen it before on Windows
CE (using a StrongArm processor) and because there aren't so many people
using SQLite with those processors, the code path is not so much tested
as the x86 case (which doesn't trigger a cpu exception, only a
performance hit).

It's up to you to confirm this is the case, but there are other things
which can be wrong, like little/big endian problems, compiler bugs
(recent platforms don't have so much testing as older ones), bad
compiler/linker options, stack overflows (because in embedded systems
you usually have a much lower default stack size), etc.

Without more info that's all I can say.


Regards,
~Nuno Lucas


-
To unsubscribe, send email to [EMAIL PROTECTED]

Re: [sqlite] met "ARM7TDMI raised an exception,data abort" when executing sqlite3Parser() in ARM environment

[Sarah]

I've got the reason. That is because some stupid mistake I've made.

During the execution of sqlite3Parser(), realloc() is called. Because here 
SQLite is running in an embedded environment without OS, so I need to 
wrap realloc() of my platform. I just wrapped malloc() and free(), but forgot 
this one.

In my malloc() and free(), I have the mechanism to guarantee the alignment of 
32-bits.

Thank you very much for the help!


- Original Message - 
From: "Barrass, Richard" <[EMAIL PROTECTED]>
To: 
Sent: Tuesday, September 12, 2006 7:41 PM
Subject: RE: [sqlite] met "ARM7TDMI raised an exception,data abort" when 
executing sqlite3Parser() in ARM environment


Hi

We have sqlite (v3.3.7) running on an os-less ARM based platform - we
use MINGW cross compilers (GCC3.4.4) - from CodeSourcery.

There was an issue earlier on that seems to be an issue with 64 bit
support - we switched off the 64bit support in the compilation of the
sqlite library and this for now has got the data base up and running on
our platform.

Richard



-Original Message-
From: Nuno Lucas [mailto:[EMAIL PROTECTED] 
Sent: 11 September 2006 21:12
To: sqlite-users@sqlite.org
Subject: Re: [sqlite] met "ARM7TDMI raised an exception,data abort" when
executing sqlite3Parser() in ARM environment


[forgot to reply to the list]

-- Forwarded message --
From: Nuno Lucas <[EMAIL PROTECTED]>
Date: Sep 11, 2006 9:07 PM
Subject: Re: Re: [sqlite] met "ARM7TDMI raised an exception,data abort"
when executing sqlite3Parser() in ARM environment
To: [EMAIL PROTECTED]


On 9/11/06, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> I don't think NULL callback and error pointer will be the reason. 
> Because I've seen this kind of usage in the list for several times.

As I said earlier, I don't think this is the reason also. Just one more
thing you could check.

> Anyway, I'll try later and report the result to the list.
>
> If it is a misaligned-pointer problem, what can I do?
>
> I don't make any change to the sqlite source code, how should this 
> happen? I can run it correctly on PC(windows XP), why can't in an 
> embedded environment? I'm confused...

You are aware they are completely different architectures, don't you?

You also didn't specify what OS you are running, which could make it
easier to get help from other experienced programmers for your platform
(if you are using CodeWarrior I would guess it's not Windows CE).

A misaligned-pointer can never occur on Windows (desktop editions, not
Windows CE), because Windows only runs on the Intel x86 processor
family, which mask that kind of things from you (although you usually
have a performance hit).

Basically it means you are accessing memory that is not aligned to the
minimum granularity the processor supports (which depends on the
processor and processor mode, but usually is 32 bits - 4 bytes - for
32-bits cpus, 64 bits - 8 bytes - for 64-bits cpus, etc).

I don't know if that is your case, but I have seen it before on Windows
CE (using a StrongArm processor) and because there aren't so many people
using SQLite with those processors, the code path is not so much tested
as the x86 case (which doesn't trigger a cpu exception, only a
performance hit).

It's up to you to confirm this is the case, but there are other things
which can be wrong, like little/big endian problems, compiler bugs
(recent platforms don't have so much testing as older ones), bad
compiler/linker options, stack overflows (because in embedded systems
you usually have a much lower default stack size), etc.

Without more info that's all I can say.


Regards,
~Nuno Lucas


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[sqlite] Re: met "ARM7TDMI raised an exception,data abort" when executing sqlite3Parser() in ARM environment

[Sarah]

plus, I'm using sqlite-source-3_3_5.

I also find a wired phenomenon:

When I trace into sqlite3Parser(pEngine, TK_SEMI, pParse->sLastToken, pParse);

the next executed statement pointed by debugger does not match with the real 
one, It seems there are one or two lines space. That is to say, the debugger 
arrow doesn't point to the real statement which is going to be executed next.


  - Original Message - 
  From: Sarah 
  To: sqlite-users@sqlite.org 
  Sent: Monday, September 11, 2006 7:22 PM
  Subject: met "ARM7TDMI raised an exception,data abort" when executing 
sqlite3Parser() in ARM environment


  Hi,all

  During the execution of a test program in an embedded environment, 
  after it goes into 
sqlite3_exec()-->sqlite3_prepare()-->sqlite3RunParser(, zSql, ),
  the debugger pops "the ARM7TDMI raised an exception,data abort" when the 
following sentence is executed(bold and underlined):

  ...
  abort_parse:
 ...  
 sqlite3Parser(pEngine, TK_SEMI, pParse->sLastToken, pParse);
 ...

  After "data abort" happens, the debugger stops at assembly languages like 
this(pointed by an arrow):
  ...
  [0xbc38]   pop  {r3-r5}
  [0xbc08]   pop  {r3}
  [0x4718]   bx   r3
  [0x6868]   ldr  r0,[r5,#4]
  [0x1c29]   mov  r1,r5
  [0x2800]   cmp  r0,#0
  [0xd018]   beq  0x42fc4  ; (__Heap_Alloc + 0x5a)
  --> [0x6802]   ldr  r2,[r0,#0]
  [0x42a2]   cmp  r2,r4
  [0xd311]   bcc  0x42fbc  ; (__Heap_Alloc + 0x52)
  [0x1c23]   mov  r3,r4
  [0x6802]   ldr  r2,[r0,#0]
  ...

  When I trace into sqlite3Parser(),it seems like the error is caused by 
"yy_reduce(yypParser,yyact-YYNSTATE);"

  My test program is like this: 
  {
   char * database = ":memory:";
   sqlite3 * db;
   
   sqlite3_open(database, );
   
   sqlite3_exec(db, "create table myt(age smallint)", NULL, NULL, NULL);
   
  }

  sqlite3_open() runs successfully.
  And CPU type is ARM7TDMI, no operating system is used, such as linux.

  I'm totally confused. Please help me diagnose this error.
  Any little help will be appreciated.

  Sarah

[sqlite] met "ARM7TDMI raised an exception,data abort" when executing sqlite3Parser() in ARM environment

[Sarah]

Hi,all

During the execution of a test program in an embedded environment, 
after it goes into 
sqlite3_exec()-->sqlite3_prepare()-->sqlite3RunParser(, zSql, ),
the debugger pops "the ARM7TDMI raised an exception,data abort" when the 
following sentence is executed(bold and underlined):

...
abort_parse:
   ...  
   sqlite3Parser(pEngine, TK_SEMI, pParse->sLastToken, pParse);
   ...

After "data abort" happens, the debugger stops at assembly languages like 
this(pointed by an arrow):
...
[0xbc38]   pop  {r3-r5}
[0xbc08]   pop  {r3}
[0x4718]   bx   r3
[0x6868]   ldr  r0,[r5,#4]
[0x1c29]   mov  r1,r5
[0x2800]   cmp  r0,#0
[0xd018]   beq  0x42fc4  ; (__Heap_Alloc + 0x5a)
--> [0x6802]   ldr  r2,[r0,#0]
[0x42a2]   cmp  r2,r4
[0xd311]   bcc  0x42fbc  ; (__Heap_Alloc + 0x52)
[0x1c23]   mov  r3,r4
[0x6802]   ldr  r2,[r0,#0]
...

When I trace into sqlite3Parser(),it seems like the error is caused by 
"yy_reduce(yypParser,yyact-YYNSTATE);"

My test program is like this: 
{
 char * database = ":memory:";
 sqlite3 * db;
 
 sqlite3_open(database, );
 
 sqlite3_exec(db, "create table myt(age smallint)", NULL, NULL, NULL);
 
}

sqlite3_open() runs successfully.
And CPU type is ARM7TDMI, no operating system is used, such as linux.

I'm totally confused. Please help me diagnose this error.
Any little help will be appreciated.

Sarah

Re: [sqlite] How to edit Makefile.linux-gcc to define those SQLITE_OMIT_*?

[Sarah]

Hi,

I've added the following lines in the Makefile.linux-gcc file:

OPTS += -DSQLITE_OMIT_ALTERTABLE

OPTS += -DSQLITE_OMIT_AUTHORIZATION 

OPTS += -DSQLITE_OMIT_AUTOVACUUM

OPTS += -DSQLITE_OMIT_AUTOINCREMENT 

OPTS += -DSQLITE_OMIT_BLOB_LITERAL

OPTS += -DSQLITE_OMIT_COMPLETE 

OPTS += -DSQLITE_OMIT_COMPOUND_SELECT

OPTS += -DSQLITE_OMIT_CONFLICT_CLAUSE 

OPTS += -DSQLITE_OMIT_EXPLAIN

OPTS += -DSQLITE_OMIT_FLOATING_POINT 

OPTS += -DSQLITE_OMIT_FOREIGN_KEY

OPTS += -DSQLITE_OMIT_INTEGRITY_CHECK 

OPTS += -DSQLITE_OMIT_PAGER_PRAGMAS

OPTS += -DSQLITE_OMIT_PRAGMA

OPTS += -DSQLITE_OMIT_REINDEX 

OPTS += -DSQLITE_OMIT_SCHEMA_PRAGMAS

OPTS += -DSQLITE_OMIT_SCHEMA_VERSION_PRAGMAS 

OPTS += -DSQLITE_OMIT_SUBQUERY

OPTS += -DSQLITE_OMIT_TCL_VARIABLE

OPTS += -DSQLITE_OMIT_TRIGGER

OPTS += -DSQLITE_OMIT_DATETIME_FUNCS



but the result is still the same. The footprint has not been changed.



And during make, I noticed that these new-added -DSQLITE_OMIT_XX did not 
appeared in the command lines.



Why? Is there any other file I need to update?



Thanks in advance.


- Original Message - 
From: <[EMAIL PROTECTED]>
To: <sqlite-users@sqlite.org>
Sent: Friday, August 25, 2006 6:35 PM
Subject: Re: [sqlite] How to edit Makefile.linux-gcc to define those 
SQLITE_OMIT_*?


"Sarah" <[EMAIL PROTECTED]> wrote:
> Hi,all
> 
> In order to define those SQLITE_OMIT_TRIGGER,SQLITE_OMIT_ALTERTABLE..., I 
> have to rebuild parse.c 
> from parse.y. So I took the following steps to do it under linux(Fedora 2). 
> 
> But by comparing the generated static library, I find that no difference has 
> been made 
> and the footprint is still the same. 
> 
> I'm not familiar with linux. So I guess the way I edit Makefile.linux-gcc is 
> wrong. 
> My steps are as follows:
> 1.Edit Makefile.linux-gcc,add the following sentences directly into it:
>   -DSQLITE_OMIT_TRIGGER
>   -DSQLITE_OMIT_ALTERTABLE
>   -DSQLITE_OMIT_VIEW
>   -DSQLITE_OMIT_AUTHORIZATION

Should be:

  OPTS += -DSQLITE_OMIT_TRIGGER

and so forth.

>   ...
> 2.run ..>../configure
> 3.run ..>make
> 4.generate lib, run ..>ar cr libsqlite.a *.o
> 5.compare the footprint of generated sqlite.a with the one without defining 
> -DSQLITE_OMIT_* in Makefile.linux-gcc.
>   totally the same.
> 
> Any help will be appreciated..
> 
> Sarah



-
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[sqlite] How to edit Makefile.linux-gcc to define those SQLITE_OMIT_*?

[Sarah]

Hi,all

In order to define those SQLITE_OMIT_TRIGGER,SQLITE_OMIT_ALTERTABLE..., I have 
to rebuild parse.c 
from parse.y. So I took the following steps to do it under linux(Fedora 2). 

But by comparing the generated static library, I find that no difference has 
been made 
and the footprint is still the same. 

I'm not familiar with linux. So I guess the way I edit Makefile.linux-gcc is 
wrong. 
My steps are as follows:
1.Edit Makefile.linux-gcc,add the following sentences directly into it:
  -DSQLITE_OMIT_TRIGGER
  -DSQLITE_OMIT_ALTERTABLE
  -DSQLITE_OMIT_VIEW
  -DSQLITE_OMIT_AUTHORIZATION
  ...
2.run ..>../configure
3.run ..>make
4.generate lib, run ..>ar cr libsqlite.a *.o
5.compare the footprint of generated sqlite.a with the one without defining 
-DSQLITE_OMIT_* in Makefile.linux-gcc.
  totally the same.

Any help will be appreciated..

Sarah

[sqlite] a problem met in tracing

[Sarah]

Hi,everyone,

I have ported SQLite to an embedded platform. When I debugged on this platform, 
I met following problems:
1. in process_input(), part of codes are like this:
   ..
   open_db(p);
   rc = sqlite3_exec(p->db, zSql, NULL, p, );
   ..
  it's strange that, after sqlite3_exec executed, it didn't return back to 
process_input(), but returned to 
  the next statement of sqlite3_exec() in function sqlite3InitCallback().

  What's the possible reason for this?

2. What is the consequence of defining SQLITE_OMIT_DISKIO? that is to say, what 
the DISKIO do? 

3.When I define #define SQLITE_OMIT_ALTERTABLE and #define SQLITE_OMIT_TRIGGER 
in my program, it caused a lot
of compiling and linking errors, most of them comes form parse.o. How to fix 
these errors?

Any guide will be appreciated.


   

[sqlite] why I can't find the implementation of functions in IoMethod structure?

[Sarah]

Why I can't find the implementation of functions(xClose, xRead, xWrite, 
xSeek) in IoMethod in the whole SQLite project?

Are these functions implemented in OS level? 

Can anyone help me?

Re: [sqlite] Another question about RAM

[Sarah]

Can anyone give me some guide?


- Original Message - 
From: "Sarah" <[EMAIL PROTECTED]>
To: <sqlite-users@sqlite.org>
Sent: Thursday, July 27, 2006 3:47 PM
Subject: [sqlite] Another question about RAM


> Hi, all
> 
> I want to build SQLite on the uc/os-II kernel in an embedded device.
> 
> Because uc/os-II doesn't provide malloc(), free() to manage memory, instead,
> it divides the memory into fixed-length blocks and provides OSMemGet() and 
> OSMemPut() to 
> get and put fixed-length memory block.
> 
> In order to port SQLite, I have to wrap uc/os-II with a set of standard 
> memory management APIs(malloc, free...).
> So I need to decide in advance that which 'fixed length' will be better. That 
> is to say, when using malloc() to 
> allocate memory in SQLite, how much memory is needed in most cases? what does 
> it depend on?
> 
> Thanks.
> 
>

[sqlite] Another question about RAM

[Sarah]

Hi, all

I want to build SQLite on the uc/os-II kernel in an embedded device.

Because uc/os-II doesn't provide malloc(), free() to manage memory, instead,
it divides the memory into fixed-length blocks and provides OSMemGet() and 
OSMemPut() to 
get and put fixed-length memory block.

In order to port SQLite, I have to wrap uc/os-II with a set of standard memory 
management APIs(malloc, free...).
So I need to decide in advance that which 'fixed length' will be better. That 
is to say, when using malloc() to 
allocate memory in SQLite, how much memory is needed in most cases? what does 
it depend on?

Thanks.

[sqlite] How to configure to reduce the RAM consumption?

[Sarah]

Hi, all

I'm using SQLite in an embedded device with uc/os-II OS kernel.

Due to the extremely limited RAM size, I have to config the SQLite somehow
to reduce the RAM consumption as much as possible.

I guess there are some actions I can take, for instance, to disable
page cache, to use hard disk(here is EEPROM) as temp. Right?

But how? Can anyone guide me?

Any other action I can take besides above?


By the way, if I don't need to use lock mechanism in my device, can I disable 
it? how?

Thanks.

Re: [sqlite] How to port SQLite to a uc/os-II OS with customized file system?

[Sarah]

Thank you for your advice.

If  I skip the functionality of file locking, that is to say, in my project, I 
do not need to use the 
functionality of file locking, then which approach will be easier for me to 
wrap my self-defined 
file system to a set of standard interfaces？
One is to wrap it to fit os_win.c;
The other one is to wrap it to fit os_unix.c;


- Original Message - 
From: "Christian Smith" <[EMAIL PROTECTED]>
To: <sqlite-users@sqlite.org>
Sent: Wednesday, June 21, 2006 7:04 PM
Subject: Re: [sqlite] How to port SQLite to a uc/os-II OS with customized file 
system?


Ҷ uttered:

> Hi,all
>
> I'm trying to bulid a database engine based on uc/os-II RTOS with my own 
> customized file system(similar with FAT16, but not exactly the same). I 
> find that SQLite is a good choice.
>
> I have read the SQLite source code for several days, but I still have no 
> idea where I should begin with.
>
> SQLite is a db engine totally based on disk file. So I guess most of my 
> future work should be to wrap my self-defined file system to have the 
> same interface as needed in os_win.c. Is it correct?
>
> Could anyone give me some advice?


Implement the interface defined by "struct IoMethod" in os.h. Use the 
existing os_*.c as templates, yes.

If you can provide a largely posix like interface to your file system, you 
could use os_unix.c largely unchanged. You might want to strip out the 
nightmare locking code, though:)


>
> Another question:
>
> Because my project will run in an embedded environment, so I have to 
> take care of the RAM consumption. I have went through the mail list, but 
> not found the description of minimum RAM usage.
>
> Could anyone tell me how much RAM is needed to run SQLite in an embedded 
> environment?


That depends. SQLite can have functionality conditionally compiled out, 
reducing it's size. The front page (http://www.sqlite.org/) proclaims:
"Small code footprint: less than 250KiB fully configured or less than
  150KiB with optional features omitted."

YMMV. Your best bet is to choose the features you don't need, compile up 
your target library, and measure the code size yourself.


>
> Thanks in advance!
>
> Best regards,
>
> Sarah


Christian


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