NAME

gendba.pl - line mode for Genezzo database system

SYNOPSIS

gendba [options]

Options:

-help            brief help message
-man             full documentation
-init            build a gnz_home installation if necessary
-gnz_home        supply a directory for the gnz_home
-shutdown        do not startup
-define key=val  define a configuration parameter

-fileheader_define key=val  define a file-specific configuration 
                            parameter (not useful in general)

OPTIONS

-help

Print a brief help message and exits.

-man

Prints the manual page and exits.

-init

Build the gnz_home dictionary and default tablespace if 
it does not exist.

-gnz_home

Supply the location for the gnz_home installation.  If 
specified, it overrides the GNZ_HOME environment variable.

-shutdown

If initializing a new database, then shutdown when 
complete, versus continuing in interactive mode.

-define key=value

Define a configuration parameter for database
creation and/or initialization.  Some important 
database creation parameters are blocksize and dbsize, 
which define the size of database blocks and
the size of the initial database file.  An important
initialization parameter is use_havok=0, which 
disables the havok extensibility subsystem on database
startup. Use "gendba.pl -define help=help" 
for more information.

-fileheader_define key=value

Define a file-specific configuration parameter when the database 
is created.  For specialized extensions which cannot use the dictionary
preference table.

DESCRIPTION

Genezzo is an extensible, persistent datastore that uses a subset of SQL. The gendba line-mode tool lets users interactively perform management tasks, as well as define and modify tables, and manipulate table data with updates and queries.

Commands

Genezzo supports some very basic SQL create/drop/alter/describe table, select, insert, update and delete syntax, and like standard SQL, table and column names are case-insensitive unless quoted. More complex SQL parses, but is ignored. The only supported functions are count(*) and ecount(*), a non-blocking count estimation function. The database also supports commit to force changes to disk, but no rollback. NOTE: Data definition (such as create table or ct) must be manually committed to keep the database in a consistent state. Uncommitted inserts and updates will only be block-consistent -- there is no guarantee that the data will get flushed to disk, and no guarantee whether the changes will or will not take effect.

rem  Some simple SELECTs
select * from _col1;
select rid, rownum, tname, colname from _col1;
select count(*) from _col1;
select ecount(*) from _col1;

rem  SELECTs with WHERE, perl and SQL style.
select * from _tab1 where tname =~ m/col/;
select * from _tab1 where tid < 5;
select * from _tab1 where numcols > 3 AND numcols < 6;

rem basic joins
select * from _tab1, _col1  where _tab1.tid = _col1.tid 
 and _tab1.tname =~ m/col/;

rem  Column aliases and Expressions
select tid as Table_ID, tname Name, (tid+1)/2 from _tab1;

rem  Basic INSERT
insert into test1 values ('a','b','c','d');
insert into test1(col2, col1) values ('a','b','c','d');

rem CREATE TABLE and INSERT...SELECT
create table test2(col1 char, col2 char);
insert into test2 (col1) select col1 from test1;

rem  DELETE with WHERE
delete from test1 where col1 < 'bravo' and col2 > 5;

rem  UPDATE with WHERE (no subqueries supported)
update test2 set col2 = 'foo' where col2 is null;

rem CREATE an INDEX
create index test1_ix on test1(col1);

rem ADD a CHECK CONSTRAINT
alter table test2 add constraint t2_cn1 check (col2 =~ m/(a|b|c|d)/x );

commit

Genezzo also supports the following "short" commands: ct, dt, s, i, d, u

ct - create table

example: ct EMP NAME=c ID=n
SQL equivalent: CREATE TABLE EMP (NAME CHAR(10), ID NUMBER) ;

dt - drop table

example: dt EMP
SQL equivalent: DROP TABLE EMP ;

s - select

example: s EMP *
SQL equivalent: SELECT * FROM EMP ;

example: s EMP rid rownum *
SQL equivalent: SELECT ROWID, ROWNUM, * FROM EMP ;

example: s EMP NAME
SQL equivalent: SELECT NAME FROM EMP ;

i - insert

example: i EMP bob 1 orville 2
SQL equivalent: 
  INSERT INTO EMP VALUES ('bob', '1');
  INSERT INTO EMP VALUES ('orville', '2'); 

d, u - delete and update

DELETE and UPDATE only work by rid 
-- you cannot specify a predicate.

example: d emp 1.2.3
SQL equivalent: DELETE FROM EMP WHERE RID='1.2.3' ;

example: u emp 1.2.3 wilbur 4
SQL equivalent: UPDATE EMP SET NAME='wilbur', 
                               ID='4' WHERE RID='1.2.3' ;

Genezzo stores information in a couple of subsidiary files: the default install creates a file called default.dbf which contains the basic dictionary information. Other data files can be added as needed. While the default configuration uses a single, fixed-size datafile, Genezzo can be configured to use datafiles that grow to some maximum size, and it can also be configured to automatically create new datafiles as necessary.

All tables are currently created in the system tablespace.

There are a couple of other useful commands:

HELP -- give useless help

DUMP -- dump out internal data structures

DUMP TABLES - list all tables

DUMP TS - dump tablespace information

RELOAD - reload all Genezzo perl modules (will lose uncommited changes, though)

COMMIT - force write of changes to database. Note that even CREATE TABLE is transactional -- you have to commit to update the persistent dictionary. Forgetting to commit can cause weird behaviors, since the buffer cache may flush data out to the dbf file. Then you can have the condition where the tablespace reuses these "empty" blocks and they already have data in them.

Environment

GNZ_HOME: If the user does not specify a gnz_home directory using the '-gnz_home' option, Genezzo stores dictionary and table information in the location specified by this variable. If GNZ_HOME is undefined, the default location is $HOME/gnz_home.

AUTHORS

Copyright (c) 2003, 2004, 2005 Jeffrey I Cohen. All rights reserved.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  US

Address bug reports and comments to: jcohen@genezzo.com

For more information, please visit the Genezzo homepage at http://www.genezzo.com