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DBI::SQL::Nano - a very tiny SQL engine
BEGIN { $ENV{DBI_SQL_NANO}=1 } # forces use of Nano rather than SQL::Statement
use DBI::SQL::Nano;
use Data::Dumper;
my $stmt = DBI::SQL::Nano::Statement->new(
"SELECT bar,baz FROM foo WHERE qux = 1"
) or die "Couldn't parse";
print Dumper $stmt;
DBI::SQL::Nano is meant as a *very* minimal SQL engine for use in situations where SQL::Statement is not available. In most situations you are better off installing SQL::Statement although DBI::SQL::Nano may be faster for some very simple tasks.
DBI::SQL::Nano, like SQL::Statement is primarily intended to provide a SQL engine for use with some pure perl DBDs including DBD::DBM, DBD::CSV, DBD::AnyData, and DBD::Excel. It isn't of much use in and of itself. You can dump out the structure of a parsed SQL statement, but that's about it.
By default, when a DBD uses DBI::SQL::Nano, the module will look to see if SQL::Statement is installed. If it is, SQL::Statement objects are used. If SQL::Statement is not available, DBI::SQL::Nano objects are used.
In some cases, you may wish to use DBI::SQL::Nano objects even if SQL::Statement is available. To force usage of DBI::SQL::Nano objects regardless of the availability of SQL::Statement, set the environment variable DBI_SQL_NANO to 1.
You can set the environment variable in your shell prior to running your script (with SET or EXPORT or whatever), or else you can set it in your script by putting this at the top of the script:
BEGIN { $ENV{DBI_SQL_NANO} = 1 }
Here's a pseudo-BNF. Square brackets [] indicate optional items; Angle brackets <> indicate items defined elsewhere in the BNF.
statement ::=
DROP TABLE [IF EXISTS] <table_name>
| CREATE TABLE <table_name> <col_def_list>
| INSERT INTO <table_name> [<insert_col_list>] VALUES <val_list>
| DELETE FROM <table_name> [<where_clause>]
| UPDATE <table_name> SET <set_clause> <where_clause>
| SELECT <select_col_list> FROM <table_name> [<where_clause>]
[<order_clause>]
the optional IF EXISTS clause ::=
* similar to MySQL - prevents errors when trying to drop
a table that doesn't exist
identifiers ::=
* table and column names should be valid SQL identifiers
* especially avoid using spaces and commas in identifiers
* note: there is no error checking for invalid names, some
will be accepted, others will cause parse failures
table_name ::=
* only one table (no multiple table operations)
* see identifier for valid table names
col_def_list ::=
* a parens delimited, comma-separated list of column names
* see identifier for valid column names
* column types and column constraints may be included but are ignored
e.g. these are all the same:
(id,phrase)
(id INT, phrase VARCHAR(40))
(id INT PRIMARY KEY, phrase VARCHAR(40) NOT NULL)
* you are *strongly* advised to put in column types even though
they are ignored ... it increases portability
insert_col_list ::=
* a parens delimited, comma-separated list of column names
* as in standard SQL, this is optional
select_col_list ::=
* a comma-separated list of column names
* or an asterisk denoting all columns
val_list ::=
* a parens delimited, comma-separated list of values which can be:
* placeholders (an unquoted question mark)
* numbers (unquoted numbers)
* column names (unquoted strings)
* nulls (unquoted word NULL)
* strings (delimited with single quote marks);
* note: leading and trailing percent mark (%) and underscore (_)
can be used as wildcards in quoted strings for use with
the LIKE and CLIKE operators
* note: escaped single quote marks within strings are not
supported, neither are embedded commas, use placeholders instead
set_clause ::=
* a comma-separated list of column = value pairs
* see val_list for acceptable value formats
where_clause ::=
* a single "column/value <op> column/value" predicate, optionally
preceded by "NOT"
* note: multiple predicates combined with ORs or ANDs are not supported
* see val_list for acceptable value formats
* op may be one of:
< > >= <= = <> LIKE CLIKE IS
* CLIKE is a case insensitive LIKE
order_clause ::= column_name [ASC|DESC]
* a single column optional ORDER BY clause is supported
* as in standard SQL, if neither ASC (ascending) nor
DESC (descending) is specified, ASC becomes the default
Tim Bunce provided the original idea for this module, helped me out of the tangled trap of namespace, and provided help and advice all along the way. Although I wrote it from the ground up, it is based on Jochen Weidmann's orignal design of SQL::Statement, so much of the credit for the API goes to him.
This module is written and maintained by
Jeff Zucker < jzucker AT cpan.org >
Copyright (C) 2004 by Jeff Zucker, all rights reserved.
You may freely distribute and/or modify this module under the terms of either the GNU General Public License (GPL) or the Artistic License, as specified in the Perl README file.