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  • Create schema error (unknown database schema '')

    Andrey Devyatka
    4 years ago
    Permalink
    Raw Message
    Hi,
    Please tell me, can I use the static library in the following case:

    library.hpp:
    #ifndef _CPP_ODB_STATIC_LIBRARY_CPP_
    #define _CPP_ODB_STATIC_LIBRARY_CPP_
    #include <odb/database.hxx>
    odb::database* createDb(void);
    #pragma db object
    struct Test
    {
    #pragma db id auto
    int m_id;
    };
    #endif // _CPP_ODB_STATIC_LIBRARY_CPP_

    library.cpp:
    #include <odb/sqlite/database.hxx>
    #include <odb/transaction.hxx>
    #include <odb/schema-catalog.hxx>
    #include "library.hpp"
    odb::database* createDb(void)
    {
    odb::database* db = new odb::sqlite::database("test.db",
    SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE);
    odb::transaction t(db->begin());
    odb::schema_catalog::create_schema(*db);
    t.commit();
    return db;
    }

    main.cpp:
    include <iostream>
    #include <odb/exception.hxx>
    #include "library.hpp"
    int main()
    {
    try {
    odb::database* db = createDb();
    std::cout << "SUCCESS" << std::endl;
    }catch(const odb::exception& ex){
    std::cout << "ERROR: " << ex.what() << std::endl;
    }
    }

    build:
    $ odb --database sqlite --generate-schema library.hpp
    $ g++ -c library-odb.cxx library.cpp main.cpp
    $ ar cr library.a library.o library-odb.o
    $ g++ -o test1 library.o library-odb.o main.o -lodb-sqlite -lodb
    $ g++ -o test2 main.o library.a -lodb-sqlite -lodb

    test:
    $ ./test1
    SUCCESS
    $ ./test2
    ERROR: unknown database schema ''

    misc:
    $ uname -srm
    Linux 3.8.0-23-generic x86_64
    $ g++ --version | head -n1
    g++ (Ubuntu/Linaro 4.7.3-1ubuntu1) 4.7.3
    $ odb --version | head -n1
    ODB object-relational mapping (ORM) compiler for C++ 2.2.0

    Thanks!
    --
    Regards,
    Andrey
    Boris Kolpackov
    4 years ago
    Permalink
    Raw Message
    Hi Andrey,
    Post by Andrey Devyatka
    [...]
    This is exactly the same issue that we've discussed just a few days
    ago:

    http://www.codesynthesis.com/pipermail/odb-users/2013-May/001286.html

    Because your application doesn't directly reference any symbols from
    library-odb.cxx, the linker ignores library-odb.o from library.a. As
    a result the schema creation code does not end up in the executable.

    Normally this is not a problem since most application executables
    will also include code that persists objects, etc., which will
    force the linker to include all the object files from the library.

    In your test, however, all you do is create the schema. As mentioned
    in the above email, with GNU ld you can use the --whole-archive
    option to force the linker to include every object file from your
    Post by Andrey Devyatka
    $ g++ -o test2 main.o library.a -lodb-sqlite -lodb
    g++ -o test2 main.o -Wl,-whole-archive library.a -Wl,-no-whole-archive -lodb-sqlite -lodb

    Another thing that you may find useful is the 'separate' value for
    the --schema-format option. It will trigger the generation of the
    schema creation code as a separate C++ source file (library-schema.cxx).
    You can then perhaps link it directly to your executable instead of
    packaging it into a static library. See the ODB compiler command line
    documentation (man pages) for more information on this option.

    Boris
    Andrey Devyatka
    4 years ago
    Permalink
    Raw Message
    Thank you!
    ...
    --
    С уважением,
    А. П. Девятка.
     
    from:http://odb-users.codesynthesis.narkive.com/3Ms11hIV/create-schema-error-unknown-database-schema
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  • 原文地址:https://www.cnblogs.com/lidabo/p/7296416.html
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