db5.1_codegen(1)



DB5.1_CODEGEN(1)          BSD General Commands Manual         DB5.1_CODEGEN(1)

NAME
     db5.1_codegen -- generate application code for Berkeley DB

SYNOPSIS
     db5.1_codegen [-Vv] [-a api] [-i file] [-o prefix]

DESCRIPTION
     The db5.1_codegen utility generates application code to create and con-
     figure Berkeley DB database environments and databases based on a simple
     description language and writes it to one or more output files.  The gen-
     erated code may need modification, in the case of complicated applica-
     tions, but will usually significantly reduce the time required to create
     Berkeley DB applications.

     The options are as follows:

     -a api
          Generate code for the specified API (currently, only ``c'' is
          accepted).

     -i file
          Specify an input file; by default, standard input is used.

     -o prefix
          Specify an output file prefix; by default, ``application'' is used.

     -V   Write the library version number to standard output and exit.

     -v   Run in verbose mode.

     The db5.1_codegen utility exits 0 on success, and >0 if an error occurs.

C Language Specific Information
     By default, when the db5.1_codegen utility generates C-language code, the
     output file is named ``application.c''.  The output filename can be spec-
     ified with the -o option.

     At the beginning of the output file is a list of public database environ-
     ment (DB_ENV) handles and database (DB) handles, as specified by the
     description language.  The database environment handle variables are
     named ``XXX_dbenv'', where ``XXX'' is the name of the environment in the
     input specification.  For databases associated with a database environ-
     ment, the database handle variables are named ``XXX_YYY'', where ``XXX''
     is the name of the environment, and ``YYY'' is the name of the database.
     For standalone databases, the database handle variables are named
     ``XXX'', where ``XXX'' is the name of the database.

     There are two public functions in the output file: bdb_startup() and
     bdb_shutdown().  The bdb_startup() function should be called to create
     and configure the database environments and databases, and the
     bdb_shutdown() function should be called to gracefully shut down the
     environments and databases.

Specification Language
     The db5.1_codegen uses a simple description language:

     o   Lines in the input consist of white-space separated tokens.
     o   Tokens are case-insensitive.
     o   Empty lines and lines where the first non-space character is a hash
         mark (``#'') are ignored.  In addition, hash marks may appear in
         lines, in which case the content of the line from the hash mark to
         the end of the line is ignored.

     There are two top-level objects: ``environment'' and ``database'', which
     correspond to database environments and databases, respectively.  These
     top-level objects can be associated with keywords to describe their con-
     figuration and relationships.

     For example, the following input would create two standalone databases:

           database data_one {
               type btree
           }
           database data_two {
               type btree
           }

     In this case, there would be no DB_ENV handle, and the public DB handles
     would be:

           DB      *data_one;
           DB      *data_two;

     For example, the following input would create a database environment
     which contains three databases:

           environment myenv {
               database data_one {
                   type btree
               }
               database data_two {
                   type btree
               }
               database data_three {
                   type btree
               }
           }

     In this case, the public DB_ENV and DB handles would be:

           DB_ENV  *myenv_dbenv;
           DB      *myenv_data_one;
           DB      *myenv_data_two;
           DB      *myenv_data_three;

     A variety of keywords can be specified for the databases and the environ-
     ments.  For example, the cache size can be specified for the database
     environment, and the page size can be specified for the database, as well
     as for secondary relationships:

           environment myenv {
               cachesize 2 0 10
               database data_one {
                   type btree
                   pagesize 1024
               }
               database data_two {
                   primary data_one
                   secondary_offset 10 15
                   type btree
                   pagesize 32768
               }
               database data_three {
                   type btree
                   pagesize 512
               }
           }

   Environment Keywords
     environment       Start a database environment block.

                       There must be three tokens on the line: the keyword,
                       the name of the environment and an opening brace
                       (``{'').

     home              Specify the database environment home directory.

                       There must be two tokens on the line: the keyword and
                       the home directory.

     cachesize         Specify the database environment cache size.

                       There must be two tokens on the line: the keyword, the
                       gigabytes of cache, the bytes of cache, and the number
                       of caches (the number of underlying physical areas into
                       which the cache is logically divided).

     private           Specify the database environment is private.

                       There must be one token on the line: the keyword by
                       itself.

     }                 End the database environment block.

                       There must be one token on the line: the keyword by
                       itself.

   Database Keywords
     database          Start a database block.

                       There must be three tokens on the line: the keyword,
                       the name of the database and an opening brace (``{'').

     custom            Specify a custom key-comparison routine.  This is used
                       when the Btree database requires a specific sort that
                       db5.1_codegen cannot generate.  A stub key comparison
                       routine will be created and configured for the database
                       which should be modified as necessary.  See the
                       ``key_type'' keyword for more information.

                       There must be one token on the line: the keyword by
                       itself.

     dupsort           Configure the database to support sorted duplicates.

                       There must be one token on the line: the keyword by
                       itself.

     extentsize        Configure the size of the Queue database extent files.

                       There must be two tokens on the line: the keyword and
                       the extent file size, as a number of pages.

     key_type          Configure a integral type key-comparison routine.  This
                       is used when the Btree database key is an integral type
                       (such as ``unsigned int'' or ``u_int32_t'').  Any C-
                       language integral type may be specified.  See the
                       ``custom'' keyword for more information.  A Btree com-
                       parison routine based on the type of the key will be
                       created and configured.

                       There must be two tokens on the line: the keyword and
                       the type.

     pagesize          Configure the database page size.

                       There must be two tokens on the line: the keyword and
                       the page size in bytes.

     primary           Configure the database as a secondary index.  A stub
                       secondary callback routine will be created and config-
                       ured for the database, which should be modified as nec-
                       essary.  See the ``secondary_offset'' keyword for more
                       information.

                       There must be two tokens on the line: the keyword and
                       the name of the primary database for which this data-
                       base is a secondary.

     recnum            Configure the Btree database to support record number
                       access.

                       There must be one token on the line: the keyword by
                       itself.

     re_len            Configure the record length for a Queue database or a
                       fixed-length Recno database.

                       There must be two tokens on the line: the keyword and
                       the length of a record, in bytes.

     secondary_offset  Configure a secondary callback routine based on a byte
                       string found in the primary database's data item.

                       There must be three tokens on the line: the keyword,
                       the byte offset from the beginning of the primary data
                       item where the secondary key occurs, and the length of
                       the secondary key in bytes.

     transaction       Configure the database (and, by extension, the database
                       environment), to be transactional.

                       There must be one token on the line: the keyword by
                       itself.

     type              Configure the database type.

                       There must be two tokens on the line: the keyword and
                       the type, where the type is one of ``btree'', ``hash'',
                       ``queue'' or ``recno''.

     }                 End the database environment block.

                       There must be one token on the line: the keyword by
                       itself.

AUTHORS
     Thorsten Glaser <tg@debian.org> wrote this manual page for the Debian
     project (but may be used by others) after the original HTML format docu-
     mentation Copyright (C) 1996,2008 Oracle. All rights reserved.

Berkeley DB                    January 12, 2011                    Berkeley DB

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