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Sqlite gen_server port for Erlang. Creates, reads and writes to sqlite database.

License: Other

Makefile 0.04% C 98.44% Erlang 1.50% Shell 0.01% M4 0.01%

erlang-sqlite3's Introduction

Erlang wrapper for SQLite3

This library allows you to work with SQLite3 databases from Erlang.

It is compatible with Windows and Linux, and should probably work on other OSes as well.

See also esqlite for an alternative library.

Requirements

Erlang/OTP R14B or later is required (tested up to 17.3 at this writing), and SQLite 3 minimum version is 3.6.1.

Compiling

Linux

Install SQLite3 by running sudo apt-get install sqlite3 or the equivalent for your package manager, or by compiling from the source.
make.

Cross-compiling

If you want to use erlang-sqlite3 on an embedded device, it can be cross-compiled.

Cross-compile SQLite3 and Erlang.
Change variables and paths in rebar.cross_compile.config.sample to the desired values and rename it to rebar.cross_compile.config.
make cross_compile.

Windows with MS Visual C++

To build both SQLite3 and sqlite3-erlang:

If MSVC tools (cl, link, etc.) are not in the path, run vcvars32.bat or vcvars64.bat depending on whether you use 32-bit or 64-bit Erlang. build_port_win32.bat and build_port_win64.bat have the standard paths for VC10.0.
nmake.

Alternately, you can use prebuilt versions of sqlite3.dll and sqlite3.def. To make sqlite3.lib, use lib /def:sqlite3.def. Then remove sqlite3.dll and sqlite3.lib targets from Makefile and do as above.

Potential compilation problems

If SQLite was built with SQLITE_OMIT_LOAD_EXTENSION option, you'll need to undefine ERLANG_SQLITE3_LOAD_EXTENSION macro in <c_src/sqlite3_drv.h>.

Running the test suite

Linux

make test

Windows

nmake tests
If you get the error "Error loading sqlite3_drv: The specified module could not be found", this is because sqlite3.dll isn't in the search path.

Example usage

See tests test/sqlite3_test.erl for a starting point. On Windows note that sqlite3.dll must be in your application's working directory or somewhere in the DLL search path.

Authors

See ./AUTHORS

erlang-sqlite3's People

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xdanos boshra-pardaz badlop brigadier nosnilmot santosh653 isabella232 xelynega

erlang-sqlite3's Issues

Where col = null

Hello

Sqlite3 expects the following syntax when when checking for NULL:

SELECT 1 FROM items WHERE col is NULL;

The query where "col = NULL" ( with equal sign ) is used, returns no records.

rebar included in repo do not work with new Erlang

When you run rebar it raises error:

deps/sqlite3$ ./rebar
escript: exception error: undefined function rebar:main/1
in function escript:run/2 (escript.erl, line 750)
in call from escript:start/1 (escript.erl, line 277)
in call from init:start_em/1
in call from init:do_boot/3

Erlang 25

Using sqlite3 from gen_server

Hello

I'm using this code:
{ok, Pid0} = sqlite3:open(DbName, [{file, TempFn1}])

Sometimes I receive errors like the following.

2023-02-21 20:35:10 =CRASH REPORT====
  crasher:
    initial call: sqlite_server:init/1
    pid: <0.866.0>
    registered_name: sqlite_server
    exception error: {{badmatch,{error,{already_started,<0.25418.0>}}},[{sqlite_server,open_db,4,[{file,"src/sqlite_se
rver.erl"},{line,324}]},{sqlite_server,handle_cast,2,[{file,"src/sqlite_server.erl"},{line,211}]},{gen_server,try_disp
atch,4,[{file,"gen_server.erl"},{line,689}]},{gen_server,handle_msg,6,[{file,"gen_server.erl"},{line,765}]},{proc_lib,
init_p_do_apply,3,[{file,"proc_lib.erl"},{line,226}]}]}
    ancestors: [<0.842.0>]
    message_queue_len: 0
    messages: []
    links: [<0.25418.0>,<0.842.0>]
    dictionary: []
    trap_exit: false
    status: running
    heap_size: 4185
    stack_size: 28
    reductions: 481871
  neighbours:
    neighbour: [{pid,<0.25418.0>},{registered_name,db_files},{initial_call,{sqlite3,init,['Argument__1']}},{current_fu
nction,{gen_server,loop,7}},{ancestors,[sqlite_server,<0.842.0>]},{message_queue_len,0},{links,[<0.866.0>,#Port<0.1391
9>]},{trap_exit,false},{status,waiting},{heap_size,376},{stack_size,12},{reductions,153},{current_stacktrace,[{gen_ser
ver,loop,7,[{file,"gen_server.erl"},{line,437}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,226}]}]}]

As I can see, the reason is in this line in sqlite3:open/2
true -> gen_server:start_link({local, DbName}, ?MODULE, Opts, [])

It starts a named process and since previous registered process exists with that name, it fails.
Docstring for that function says:

If the name is an atom other than 'anonymous', it's used for registering the gen_server and must be unique.

I think that approach is prone to errors.

Utf-8 encoding of table names

sqlite> .tables
Asetukset      Hyppääjät   Lentäjät     Pokat          Tarvikkeet   
Eurot          Hypyt          Luokat         Pondimaksut    Tyypit       
Hinnat         Koneet         Maksut         Stuff          Varjot       
Hyppymestarit  Korvaukset     Ostokset       Suoritukset

But:

([email protected])2> sqlite3:list_tables(hlu).
['Asetukset','Eurot','Hinnat','HyppÃ¤Ã¤jÃ¤t',
 'Hyppymestarit','Hypyt','Koneet','Korvaukset','LentÃ¤jÃ¤t',
 'Luokat','Maksut','Ostokset','Pokat','Pondimaksut','Stuff',
 'Suoritukset','Tarvikkeet','Tyypit','Varjot']

Although:

([email protected])3> sqlite3:sql_exec(hlu, "select count(id)i from HyppÃ¤Ã¤jÃ¤t where id >0;").    
[{columns,["i"]},{rows,[{1270}]}]

There is the very same issue of the column names also.

c_src/sqlite3_drv.c: warning: too many arguments for format [-Wformat-extra-args]

Hi,

for some reason I don't know, erlang-sqlite3 doesn't build on debian sid (a.k.a. unstable) anymore.
The Error is located in the C code.

Could be related to erlang 19.1.1 or gcc 6.2.0 or something completely different.

The complete build log is available here:
https://bugs.debian.org/839351

feature request: possibility to read db from memory

Often it is necessary to close db and upload it somewhere.
It would be good if this library allowed possibility to dump contents of database.

processone / erlang-sqlite3 Goto Github PK

erlang-sqlite3's Introduction

Erlang wrapper for SQLite3

Requirements

Compiling

Linux

Cross-compiling

Windows with MS Visual C++

Potential compilation problems

Running the test suite

Linux

Windows

Example usage

Authors

erlang-sqlite3's People

Contributors

Stargazers

Watchers

Forkers

erlang-sqlite3's Issues

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