NAME DBD::Sprite - A DBI driver for Flat Text Files SYNOPSIS use DBI; $dbh = DBI->connect("DBI:Sprite:spritedb",'user','password') or die "Cannot connect: " . $DBI::errstr; $sth = $dbh->prepare("CREATE TABLE a (id INTEGER, name CHAR(10))") or die "Cannot prepare: " . $dbh->errstr(); $sth->execute() or die "Cannot execute: " . $sth->errstr(); $sth->finish(); $dbh->disconnect(); WARNING THIS IS ALPHA SOFTWARE. It is *only* 'Alpha' because this is it's 1st release! DESCRIPTION The DBD::Sprite module is yet another driver for the DBI (Database independent interface for Perl). This one is based on the Sprite "engine" by Shishir Gurdavaram. It differs from DBD::CSV as follows: 1) It creates and works on true "databases" with user-ids and passwords, 2) The database author specifies the field delimiters, record delimiters, user, password, table file path, AND extension for each database. 3) Transactions (commits and rollbacks) are fully supported! 4) Autonumbering and user-defined functions are supported. 5) You don't need any other modules or databases. (NO prerequisites except Perl 5 and the DBI module! 6) It is not necessary to call the "$dbh->quote()" method all the time in your sql. 7) NULL is handled as an empty string. 8) Oracle Sequences are supported! 9) Numeric, Char(#), and Varchar(#) datatypes are supported! See the DBI(3) manpage for details on DBI, the JSprite(3) manpage for details on Sprite plus my extensions. Prerequisites The only system dependent feature that DBD::File uses, is the `flock()' function. Thus the module should run (in theory) on any system with a working `flock()', in particular on all Unix machines and on Windows NT. Under Windows 95 and MacOS the use of `flock()' is disabled, thus the module should still be usable, Unlike other DBI drivers, you don't need an external SQL engine or a running server. All you need is Perl modules Installation Installing this module (and the prerequisites from above) is quite simple. You just fetch the archive, extract it with gzip -cd DBD-Sprite-#.###.tar.gz | tar xf - (this is for Unix users, Windows users would prefer WinZip or something similar) and then enter the following: cd DBD-Sprite-#.### perl Makefile.PL make make test If any tests fail, let me know. Otherwise go on with make install Note that you almost definitely need root or administrator permissions. If you don't have them, read the ExtUtils::MakeMaker man page for details on installing in your own directories. the ExtUtils::MakeMaker manpage. NOTE: You may also need to copy "makesdb.pl" to /usr/local/bin or somewhere in your path. Windows install: If installing in Windows, you must 1st install the DBI module, create a DBD subdirectory in your Perl's path (run "perl -V" to find out what this is), copy "Sprite.pm" to it, then copy the other files ( JSprite.pm, OraSpriteFns.pl, and to_date.pl to the same directory you created the DBD subdirectory in. Then copy the file makesdb.pl to the directory perl itself is in. These directories (in ActivePerl) are: c:\perl\site\lib and c:\perl\bin respectively. Getting started: 1) cd to where you wish to store your database. 2) run makesdb.pl to create your database, ie. Database name: mydb Database user: me User password: mypassword Database path: . Table file extension (default .stb): Record delimiter (default \n): Field delimiter (default ::): This will create a new database text file (mydb.sdb) in the current directory. This ascii file contains the information you enterred above. To add additional user-spaces, simply rerun makesdb.pl with "mydb" as your database name, and enter additional users (name, password, path, extension, and delimiters). For an example, after running "make test", look at the file "test.sdb". When connecting to a Sprite database, Sprite will look in the current directory, then, if specified, the path in the SPRITE_HOME environment variable. The database name, user, and password are used in the "db->connect()" method described below. The "database path" is where your tables will be created and reside. Table files are ascii text files which will have, by default, the extension ".stb" (Sprite table). By default, each record will be written to a single line (separated by \n -- Windows users should probably use "\r\n"). Each field datum will be written without quotes separated by the "field delimiter (default: double-colon). The first line of the table file consists of the a field name, an equal ("=") sign, an asterisk if it is a key field, then the datatype and size. This information is included for each field and separated by the field separator. For an example, after running "make test", look at the file "testtable.stb". 3) write your script to use DBI, ie: #!/usr/bin/perl use DBI; $dbh = DBI->connect('DBI:Sprite:mydb','me','mypassword') || die "Could not connect (".$DBI->err.':'.$DBI->errstr.")!"; ... #CREATE A TABLE, INSERT SOME RECORDS, HAVE SOME FUN! 4) get your application working. 5) rehost your application on a "production" machine and change "Sprite" to a DBI driver for a "real" database! Creating and dropping tables You can create and drop tables with commands like the following: $dbh->do("CREATE TABLE $table (id INTEGER, name CHAR(64))"); $dbh->do("DROP TABLE $table"); Note that currently only the column names will be stored and no other data. Thus all other information including column type (INTEGER or CHAR(x), for example), column attributes (NOT NULL, PRIMARY KEY, ...) will silently be discarded. This may change in a later release. A drop just removes the file without any warning. See the DBI(3) manpage for more details. Table names cannot be arbitrary, due to restrictions of the SQL syntax. I recommend that table names are valid SQL identifiers: The first character is alphabetic, followed by an arbitrary number of alphanumeric characters. If you want to use other files, the file names must start with '/', './' or '../' and they must not contain white space. Inserting, fetching and modifying data The following examples insert some data in a table and fetch it back: First all data in the string: $dbh->do("INSERT INTO $table VALUES (1, 'foobar')"); Note the use of the quote method for escaping the word 'foobar'. Any string must be escaped, even if it doesn't contain binary data. Next an example using parameters: $dbh->do("INSERT INTO $table VALUES (?, ?)", undef, 2, "It's a string!"); To retrieve data, you can use the following: my($query) = "SELECT * FROM $table WHERE id > 1 ORDER BY id"; my($sth) = $dbh->prepare($query); $sth->execute(); while (my $row = $sth->fetchrow_hashref) { print("Found result row: id = ", $row->{'id'}, ", name = ", $row->{'name'}); } $sth->finish(); Again, column binding works: The same example again. my($query) = "SELECT * FROM $table WHERE id > 1 ORDER BY id"; my($sth) = $dbh->prepare($query); $sth->execute(); my($id, $name); $sth->bind_columns(undef, \$id, \$name); while ($sth->fetch) { print("Found result row: id = $id, name = $name\n"); } $sth->finish(); Of course you can even use input parameters. Here's the same example for the third time: my($query) = "SELECT * FROM $table WHERE id = ?"; my($sth) = $dbh->prepare($query); $sth->bind_columns(undef, \$id, \$name); for (my($i) = 1; $i <= 2; $i++) { $sth->execute($id); if ($sth->fetch) { print("Found result row: id = $id, name = $name\n"); } $sth->finish(); } See the DBI(3) manpage for details on these methods. See the SQL::Statement(3) manpage for details on the WHERE clause. Data rows are modified with the UPDATE statement: $dbh->do("UPDATE $table SET id = 3 WHERE id = 1"); Likewise you use the DELETE statement for removing rows: $dbh->do("DELETE FROM $table WHERE id > 1"); fn_register Method takes 2 arguments: Function name and optionally, a package name (default is "main"). $dbh->fn_register ('myfn','mypackage'); -or- use JSprite; JSprite::fn_register ('myfn',__PACKAGE__); Then, you could say in sql: insert into mytable values (myfn(?)) and bind some value to "?", which is passed to "myfn", and the return-value is inserted into the database. You could also say (without binding): insert into mytable values (myfn('mystring')) -or (if the function takes a number)- select field1, field2 from mytable where field3 = myfn(123) Return Value None Error handling In the above examples we have never cared about return codes. Of course, this cannot be recommended. Instead we should have written (for example): my($query) = "SELECT * FROM $table WHERE id = ?"; my($sth) = $dbh->prepare($query) or die "prepare: " . $dbh->errstr(); $sth->bind_columns(undef, \$id, \$name) or die "bind_columns: " . $dbh->errstr(); for (my($i) = 1; $i <= 2; $i++) { $sth->execute($id) or die "execute: " . $dbh->errstr(); if ($sth->fetch) { print("Found result row: id = $id, name = $name\n"); } } $sth->finish($id) or die "finish: " . $dbh->errstr(); Obviously this is tedious. Fortunately we have DBI's *RaiseError* attribute: $dbh->{'RaiseError'} = 1; $@ = ''; eval { my($query) = "SELECT * FROM $table WHERE id = ?"; my($sth) = $dbh->prepare($query); $sth->bind_columns(undef, \$id, \$name); for (my($i) = 1; $i <= 2; $i++) { $sth->execute($id); if ($sth->fetch) { print("Found result row: id = $id, name = $name\n"); } } $sth->finish($id); }; if ($@) { die "SQL database error: $@"; } This is not only shorter, it even works when using DBI methods within subroutines. Metadata The following attributes are handled by DBI itself and not by DBD::File, thus they should all work as expected: I have only used the last 3. Active ActiveKids CachedKids CompatMode (Not used) InactiveDestroy Kids PrintError RaiseError Warn The following DBI attributes are handled by DBD::Sprite: AutoCommit Works ChopBlanks Should Work NUM_OF_FIELDS Valid after `$sth->execute' NUM_OF_PARAMS Valid after `$sth->prepare' NAME Valid after `$sth->execute'; undef for Non-Select statements. NULLABLE Not really working. Always returns an array ref of one's, as DBD::Sprite always allows NULL (handled as an empty string). Valid after `$sth->execute'. PRECISION Works SCALE Works LongReadLen Should work LongTruncOk Works These attributes and methods are not supported: bind_param_inout CursorName In addition to the DBI attributes, you can use the following dbh attributes. These attributes are read-only after "connect". sprite_dbdir Path to tables for database. sprite_dbext File extension used on table files in the database. sprite_dbuser Current database user. sprite_dbfdelim Field delimiter string in use for the database. sprite_dbrdelim Record delimiter string in use for the database. SPRITE_HOME Environment variable specifying a path to search for Sprite databases (*.sdb) files. Driver private methods DBI->data_sources() The `data_sources' method returns a list of "databases" (.sdb files) found in the current directory and, if specified, the path in the SPRITE_HOME environment variable. $dbh->tables() This method returns a list of table names specified in the current database. Example: my($dbh) = DBI->connect("DBI:Sprite:mydatabase",'me','mypswd'); my(@list) = $dbh->func('list_tables'); Other Utilities makesdb.pl This utility lets you build new Sprite databases and later add additional user-spaces to them. Simply cd to the directory where you wish to create / modify a database, and run. It prompts as follows: Database name: Enter a 1-word name for your database. Database user: Enter a 1-word user-name. User password: Enter a 1-word password for this user. Database path: Enter a path (no trailing backslash) to store tables. Table file extension (default .stb): Record delimiter (default \n): Field delimiter (default ::): The last 6 prompts repeat until you do not enter another user-name allowing you to set up multiple users in a single database. Each "user" can have it's own separate tables by specifying different paths, file-extensions, password, and delimiters! You can invoke "makesdb.pl" on an existing database to add new users. You can edit it with vi to remove users, delete the 5 lines starting with the path for that user. The file is all text, except for the password, which is encrypted for your protection! Data restrictions Although DBD::Sprite supports the following datatypes: NUMBER FLOAT DOUBLE INT INTEGER NUM CHAR VARCHAR VARCHAR2 DATE LONG BLOB and MEMO, there are really only 3 basic datatypes (NUMBER, CHAR, and VARCHAR). This is because Perl treates everything as simple strings. The first 5 are all treated as "numbers" by Perl for sorting purposes and the rest as strings. This is seen when sorting, ie NUMERIC types sort as 1,5,10,40,200, whereas STRING types sort these as 1,10,200,40,5. CHAR fields are right- padded with spaces when stored. LONG-type fields are subject to truncation by the "LongReadLen" attribute value. DBD::Sprite works with the tieDBI module, if "Sprite => 1" lines are added to the "%CAN_BIND" and "%CAN_BINDSELECT" hashes. This should not be necessary, and I will investigate when I have time. TODO Extensions of DBD::Sprite Joins The current version of the module works with single table SELECTs only. This will be a trick, since the underlying statement object in JSprite is bound to a single file, so it may be a long wait! Additional Oracle-ish functions built-in. The currently-supported ones are "SYSTIME", "NUM", and "NULL". "NUM" does nothing, "NULL" returns an empty string. My first will probably be "TO_DATE". Whatever Mr. Gurdavaram might wish to add. KNOWN BUGS * The module is using flock() internally. However, this function is not available on platforms. Using flock() is disabled on MacOS and Windows 95: There's no locking at all (perhaps not so important on these operating systems, as they are for single users anyways). * The SQL query operators "and" and "or" must currently be *lower case*! * If fields specified in the "order-by" clause are not also fetched, ordering does not work quite right :-( AUTHOR AND COPYRIGHT This module is Copyright (C) 2000 by Jim Turner Email: jim.turner@lmco.com All rights reserved. You may distribute this module under the terms of either the GNU General Public License or the Artistic License, as specified in the Perl README file. JSprite.pm is a derived work by Jim Turner from Sprite.pm, a module written and copyrighted (c) 1995-1998, by Shishir Gurdavaram (shishir@ora.com). SEE ALSO JSprite(3), DBI(3), perl(1) For general information on DBI see http://www.symbolstone.org/technology/perl/DBI