[sqlite] Running Sqlite on 64-bit/Client-server data base

2015-12-16 Thread Simon Slavin
On 15 Dec 2015, at 11:47pm, Hamdan Alabsi wrote: > Also, does sqlite support client-server database engine ? No. Your program calls SQLite API routines. Those routines read and write the file. There is no server. Simon.

[sqlite] about attach database

2015-12-16 Thread 王庆刚
hi,all There are two ways to open a database. 1.sqlite3_open 2.ATTACH DATABASE Because there are so many data base. So we used attach database to open them. But the efficiency of the programming is not ideal. which one is faster? Is the efficiency between

[sqlite] about attach database

2015-12-16 Thread 王庆刚
I mean only compare the two ways of get the database handl. 1.sqlite3_open 2.ATTACH DATABASE Do not consider the next operation, such as select,update and so on. At 2015-12-16 10:51:31, "Richard Hipp" wrote: >On 12/15/15, ??? <2004wqg2008 at 163.com> wrote: >> hi,all >> There

[sqlite] about attach database

2015-12-16 Thread 王庆刚
After testing the Sqlite3_open and ATTACH DATABASE, I found that the attach database is slower than sqlite3_open. there is attachment after the mail which includ the speed information ( millisecond ). At 2015-12-16 10:59:27, "Richard Hipp" wrote: >On 12/15/15, ???

[sqlite] about attach database

2015-12-16 Thread 王庆刚
After testing the Sqlite3_open and ATTACH DATABASE, I found that the attach database is slower than sqlite3_open. there is attachment after the mail which includ the speed information ( millisecond ).

[sqlite] about attach database

2015-12-16 Thread Dominique Pellé
??? <2004wqg2008 at 163.com> wrote: > > After testing the Sqlite3_open and ATTACH DATABASE, > I found that the attach database is slower than sqlite3_open. > there is attachment after the mail which includ the speed > information ( millisecond ). Your attachment

[sqlite] about attach database

2015-12-16 Thread Scott Robison
On Tue, Dec 15, 2015 at 11:19 PM, Dominique Pell? wrote: > ??? <2004wqg2008 at 163.com> wrote: > > > > > After testing the Sqlite3_open and ATTACH DATABASE, > > I found that the attach database is slower than sqlite3_open. > > there is attachment after the mail which

[sqlite] Index on computed value?

2015-12-16 Thread Deon Brewis
Is it possible to have an index on a computer value? E.g. I have a 40 byte value in one of my columns. I only want an index over the first 4 bytes of it. However, I don't really want to repeat those 4 bytes inside another column on the main table. Is there any way to accomplish that? -

[sqlite] about attach database

2015-12-16 Thread Dominique Pellé
Scott Robison wrote: > On Tue, Dec 15, 2015 at 11:19 PM, Dominique Pell? gmail.com >> wrote: > >> ??? <2004wqg2008 at 163.com> wrote: >> >> > >> > After testing the Sqlite3_open and ATTACH DATABASE, >> > I found that the attach database is slower than sqlite3_open. >> >

[sqlite] bug when columns are missing in embedded subselect

2015-12-16 Thread Hick Gunter
This has been discussed several times on the list. SQLite (and all other databases) try very hard to resolve the names you refer to in your query and will search all the tables you mention to find *unqualified* references. They give up if they do not find exactly one definition. Try " delete

[sqlite] Running Sqlite on 64-bit/Client-server data base

2015-12-16 Thread R Smith
Hi Hamdan, These are some very basic questions (as others have mentioned), and may not be your only questions at this point. To fully understand how SQLite implements databasing and what it is best suited for (or what it isn't useful for), your best bet is to take a look at these pages:

[sqlite] about attach database

2015-12-16 Thread Dan Kennedy
On 12/16/2015 12:51 PM, ??? wrote: > After testing the Sqlite3_open and ATTACH DATABASE, > I found that the attach database is slower than sqlite3_open. > there is attachment after the mail which includ the speed > information ( millisecond ). Hi, This mailing list

[sqlite] Index on computed value?

2015-12-16 Thread Dan Kennedy
On 12/16/2015 03:17 PM, Deon Brewis wrote: > Is it possible to have an index on a computer value? > > > E.g. I have a 40 byte value in one of my columns. I only want an index over > the first 4 bytes of it. > > > However, I don't really want to repeat those 4 bytes inside another column on > the

[sqlite] about attach database

2015-12-16 Thread 王庆刚
Thanks for everyone. You are right. According to you help, I understand the problem. Just open or attach database , open operation is faster than attach database. if add a query statement after open or attach database. The time which they cost almost the same. Best regards. what Dominique

[sqlite] Problem with accumulating decimal values

2015-12-16 Thread E.Pasma
16 dec 2015, James K. Lowden: > On Fri, 11 Dec 2015 16:21:30 +0200 > "Frank Millman" wrote: > >> sqlite> UPDATE fmtemp SET balance = balance + 123.45; >> sqlite> SELECT bal FROM fmtemp; >> 5925.599 > > To a question like that you'll receive a lot of answers about > numerical >

[sqlite] about attach database

2015-12-16 Thread Simon Slavin
On 16 Dec 2015, at 8:37am, Dominique Pell? wrote: > Having said all that, reading https://www.sqlite.org/c3ref/open.html > I see no mention of the fact that sqlite3_open*() is lazy. > Is it documented somewhere? Not in the official SQLite documentation. But it is easy to prove. Just open a

[sqlite] Problem with accumulating decimal values

2015-12-16 Thread Keith Medcalf
> Hello, so in short, rounding the column anywhere it is used, is > another solution. I confirmed this below. Thanks, E. Pasma. > > BEGIN; > UPDATE fmtemp SET bal = ROUND(bal,2) + 123.45; > (repeat a 1.000.001 times > END; > SELECT bal FROM fmtemp; > 123450123.45 Absolutely not! You should

[sqlite] Problem with accumulating decimal values

2015-12-16 Thread Domingo Alvarez Duarte
Hello ! I said once and I'll say again for some applications it would make sense to use _Decimal64 (_Decimal32, _Decimal128) instead of floating points. Even if it's done in software the performance is acceptable on most common cases. See a sqlite3.c/sqlite3.h modified to use "_Decimal64"

[sqlite] Problem with accumulating decimal values

2015-12-16 Thread E.Pasma
16 dec 2015, Keith Medcalf: >> BEGIN; >> UPDATE fmtemp SET bal = ROUND(bal,2) + 123.45; >> (repeat a 1.000.001 times >> END; >> SELECT bal FROM fmtemp; >> 123450123.45 > > You should NEVER round as you have done above. You may get lucky > and the errors may cancel each other out, or you may get

[sqlite] Problem with accumulating decimal values

2015-12-16 Thread Bernardo Sulzbach
On Wed, Dec 16, 2015 at 9:43 AM, Keith Medcalf wrote: > >> Hello, so in short, rounding the column anywhere it is used, is >> another solution. I confirmed this below. Thanks, E. Pasma. >> >> BEGIN; >> UPDATE fmtemp SET bal = ROUND(bal,2) + 123.45; >> (repeat a 1.000.001 times >> END; >> SELECT

[sqlite] Problem with accumulating decimal values

2015-12-16 Thread Adam Devita
Good day, As a matter of interest, when calculating interest on a sum of money expressed in pennies, how do you handle int arithmetic truncating? Is that an accounting design rule thing when dealing with fractions of a penny to round? Is this an arbitrary quantization? Once upon a time there

[sqlite] Problem with accumulating decimal values

2015-12-16 Thread Simon Slavin
On 16 Dec 2015, at 3:46pm, Adam Devita wrote: > As a matter of interest, when calculating interest on a sum of money > expressed in pennies, how do you handle int arithmetic truncating? > Is that an accounting design rule thing when dealing with fractions of > a penny to round? When writing

[sqlite] Problem with accumulating decimal values

2015-12-16 Thread Bernardo Sulzbach
On Wed, Dec 16, 2015 at 1:54 PM, Simon Slavin wrote: > > On 16 Dec 2015, at 3:46pm, Adam Devita wrote: > > When writing accounting software, there will be a specific rule for rounding > attached to each calculation. For instance a process for working out a > mortgage will include its own

[sqlite] Index on computed value?

2015-12-16 Thread Zsbán Ambrus
On Wed, Dec 16, 2015 at 9:17 AM, Deon Brewis wrote: > Is it possible to have an index on a computer value? > > E.g. I have a 40 byte value in one of my columns. I only want an index over > the first 4 bytes of it. > > However, I don't really want to repeat those 4 bytes inside another column on

[sqlite] Index on computed value?

2015-12-16 Thread Simon Slavin
On 16 Dec 2015, at 4:23pm, Zsb?n Ambrus wrote: > See http://sqlite.org/expridx.html "The ability to index expressions was added to SQLite with version 3.9.0 in October of 2015" Nice to see that the development team's crystal ball is running around three months ahead of questions on this

[sqlite] Problem with accumulating decimal values

2015-12-16 Thread E.Pasma
16 dec 2015, 16:17, Bernardo Sulzbach: > > On Wed, Dec 16, 2015 at 12:05 PM, E.Pasma wrote: > >> Ok this does not work of any scale of numbers. But a solution with >> integers >> neither does >> >> E.Pasma >> > ...I like integer better than floating points and text for > currencies ... Good

[sqlite] Problem with accumulating decimal values

2015-12-16 Thread R Smith
On 2015/12/16 4:05 PM, E.Pasma wrote: > 16 dec 2015, Keith Medcalf: >>> BEGIN; >>> UPDATE fmtemp SET bal = ROUND(bal,2) + 123.45; >>> (repeat a 1.000.001 times >>> END; >>> SELECT bal FROM fmtemp; >>> 123450123.45 >> >> You should NEVER round as you have done above. You may get lucky and >>

[sqlite] about attach database

2015-12-16 Thread Scott Robison
On Wed, Dec 16, 2015 at 1:37 AM, Dominique Pell? wrote: > Scott Robison wrote: > > > Why would that be of benefit to you? Are you intending to attach a > database > > and never use it? It seems to me the same amount of time will be taken > > either way. > > > > When it comes to opening a

[sqlite] Bug with DATETIME('localtime')

2015-12-16 Thread James K. Lowden
On Sun, 13 Dec 2015 20:11:32 -0700 Scott Robison wrote: > > It's not fixed, although gacial progress is being made. Even though > > we've had the TZ database & Posix datetime functions since 1986, 30 > > years later we're still struggling with it, and not only on Windows. > > The problem would

[sqlite] Problem with accumulating decimal values

2015-12-16 Thread James K. Lowden
On Wed, 16 Dec 2015 20:33:40 +0200 R Smith wrote: > > Ok this does not work of any scale of numbers. But a solution with > > integers neither does > > I think the bit that Keith tried to highlight is that we should > always refrain from storing errors. Keith recommended against storing

[sqlite] Problem with accumulating decimal values

2015-12-16 Thread James K. Lowden
On Wed, 16 Dec 2015 15:05:34 +0100 "E.Pasma" wrote: > 16 dec 2015, Keith Medcalf: > >> BEGIN; > >> UPDATE fmtemp SET bal = ROUND(bal,2) + 123.45; > >> (repeat a 1.000.001 times > >> END; > >> SELECT bal FROM fmtemp; > >> 123450123.45 > > > > You should NEVER round as you have done above. You

[sqlite] Porting SQLITE-3.10 into VxWorks-6.9

2015-12-16 Thread Janto Ranjan Paul
Hi All,

[sqlite] Porting SQLITE-3.10 into VxWorks-6.9

2015-12-16 Thread Richard Hipp
On 12/16/15, Janto Ranjan Paul wrote: > > Hi All, > > From last couple of days, I am trying to port Sqlite-3.10 database into > Vxworks... The latest release version of SQLite is 3.9.2. Are you using unreleased code from trunk? -- D. Richard Hipp drh at sqlite.org

[sqlite] batch or one by one?

2015-12-16 Thread Scott Robison
On Wed, Dec 16, 2015 at 9:24 PM, ??? <2004wqg2008 at 163.com> wrote: > hi,all > > There is an interesting phenomenon.As you know, SQLite can retrieve > records by batch or one by one. > 1.Retrieve by batch such as sqlite3_get_table. > 2.Retrieve one by one such as