readme.ecos

来自「db.* (pronounced dee-be star) is an adva」· ECOS 代码 · 共 69 行

Using db.* with eCos
====================

db.* supports eCos as a target environment. Due to eCos' single-process
model, Lock Manager functionality is not ported yet, however it seems that
most embedded applications could easily employ single-user access mode to
the database.

Produce database definition in target independent way
=====================================================

A new db.* feature targeting embedded environments is the ability to
source-compile the database schema, so that it can be integrated into
your application at compile time. This makes your application
self-contained (you don't need to provide external .dbd file) and
byte-order independent (you can use little-endian host environment
and big-endian target). To use the source compilation supply -c flag
to ddlp, compiling your .ddl file, link the produced .c file with your
application and use d_sopen() to open database.

For example, suppose you have db.ddl file. Compile the database schema as
follows:

	# ddlp -c db.ddl

This will produce db.c and db.h files.

Now link db.c into your application and open the database in the following way:

	#include "db.h"
	
	int main()
	{
		...
		
		/* prepare database to be used */
		d_sopen(&db_dbd, "o", task);
		
		/* we couldn't use initdb, so let's do it now */
		d_initialize(task, CURR_DB);
		...
	}

Install db.* on eCos
====================

db.* installation is done using a two step process: first build the eCos
package and then install it.

1) Skip this step if you have dowloaded db.* eCos package. Build the eCos
package by changing the current directory to db.ecos and running make:

	# (cd db.ecos; make)
	
this would produce db.ecos.epk.

2) Install the package using the standard ecos installer:

	# ecosadmin.tcl add db.ecos.epk
	
or using the supplied makefile target:

	# make install

Now you can configure your eCos target environment. Include the "db.eCos
database library" package in your configuration, and also include the Posix
thread layer, stdio support, and wide char support.