"new"
• "SQL::SplitStatement->new( %options )"
• "SQL::SplitStatement->new( \%options )"
It creates and returns a new SQL::SplitStatement object. It accepts its options either as a hash or a
hashref.
"new" takes the following Boolean options, which for documentation purposes can be grouped in two sets:
"Formatting Options" and "DBMSs Specific Options".
FormattingOptions
• "keep_terminators"
A Boolean option which causes, when set to a false value (which is the default), the trailing
terminator token to be discarded in the returned atomic statements. When set to a true value, the
terminators are kept instead.
The possible terminators (which are treated as such depending on the context) are:
• ";" (the semicolon character);
• any string defined by the MySQL "DELIMITER" command;
• an ";" followed by an "/" (forward-slash character) on its own line;
• an ";" followed by an "." (dot character) on its own line, followed by an "/" on its own line;
• an "/" on its own line regardless of the preceding characters (only if the "slash_terminates"
option, explained below, is set).
The multi-line terminators above are always treated as a single token, that is they are discarded (or
returned) as a whole (regardless of the "slash_terminates" option value).
If your statements are to be fed to a DBMS, you are advised to keep this option to its default
(false) value, since some drivers/DBMSs don't want the terminator to be present at the end of the
(single) statement.
(Note that the last, possibly empty, statement of a given SQL text, never has a trailing terminator.
See below for an example.)
• "keep_terminator"
An alias for the the "keep_terminators" option explained above. Note that if "keep_terminators" and
"keep_terminator" are both passed to "new", an exception is thrown.
• "keep_extra_spaces"
A Boolean option which causes, when set to a false value (which is the default), the spaces ("\s")
around the statements to be trimmed. When set to a true value, these spaces are kept instead.
When "keep_terminators" is set to false as well, the terminator is discarded first (regardless of the
spaces around it) and the trailing spaces are trimmed then. This ensures that if "keep_extra_spaces"
is set to false, the returned statements will never have trailing (nor leading) spaces, regardless of
the "keep_terminators" value.
• "keep_comments"
A Boolean option which causes, when set to a false value (which is the default), the comments to be
discarded in the returned statements. When set to a true value, they are kept with the statements
instead.
Both SQL and multi-line C-style comments are recognized.
When kept, each comment is returned in the same string with the atomic statement it belongs to. A
comment belongs to a statement if it appears, in the original SQL code, before the end of that
statement and after the terminator of the previous statement (if it exists), as shown in this pseudo-
SQL snippet:
/* This comment
will be returned
together with statement1 */
<statement1>; -- This will go with statement2
-- (note the semicolon which closes statement1)
<statement2>
-- This with statement2 as well
• "keep_empty_statements"
A Boolean option which causes, when set to a false value (which is the default), the empty statements
to be discarded. When set to a true value, the empty statements are returned instead.
A statement is considered empty when it contains no characters other than the terminator and space
characters ("\s").
A statement composed solely of comments is not recognized as empty and may therefore be returned even
when "keep_empty_statements" is false. To avoid this, it is sufficient to leave "keep_comments" to
false as well.
Note instead that an empty statement is recognized as such regardless of the value of the options
"keep_terminators" and "keep_extra_spaces".
These options are basically to be kept to their default (false) values, especially if the atomic
statements are to be given to a DBMS.
They are intended mainly for cosmetic reasons, or if you want to count by how many atomic statements,
including the empty ones, your original SQL code was composed of.
Another situation where they are useful (in the general case necessary, really), is when you want to
retain the ability to verbatim rebuild the original SQL string from the returned statements:
my $verbatim_splitter = SQL::SplitStatement->new(
keep_terminators => 1,
keep_extra_spaces => 1,
keep_comments => 1,
keep_empty_statements => 1
);
my @verbatim_statements = $verbatim_splitter->split($sql_string);
$sql_string eq join '', @verbatim_statements; # Always true, given the constructor above.
Other than this, again, you are recommended to stick with the defaults.
DBMSsSpecificOptions
The same syntactic structure can have different semantics across different SQL dialects, so sometimes it
is necessary to help the parser to make the right decision. This is the function of these options.
• "slash_terminates"
A Boolean option which causes, when set to a true value (which is the default), a "/" (forward-slash)
on its own line, even without a preceding semicolon, to be admitted as a (possible) terminator.
If set to false, a forward-slash on its own line is treated as a statement terminator only if
preceded by a semicolon or by a dot and a semicolon.
If you are dealing with Oracle's SQL, you should let this option set, since a slash (alone, without a
preceding semicolon) is sometimes used as a terminator, as it is permitted by SQL*Plus (on non-block
statements).
With SQL dialects other than Oracle, there is the (theoretical) possibility that a slash on its own
line can pass the additional checks and be considered a terminator (while it shouldn't). This chance
should be really tiny (it has never been observed in real world code indeed). Though negligible, by
setting this option to false that risk can anyway be ruled out.
"split"
• "$sql_splitter->split( $sql_string )"
This is the method which actually splits the SQL code into its atomic components.
It returns a list containing the atomic statements, in the same order they appear in the original SQL
code. The atomic statements are returned according to the options explained above.
Note that, as mentioned above, an SQL string which terminates with a terminator token (for example a
semicolon), contains a trailing empty statement: this is correct and it is treated accordingly (if
"keep_empty_statements" is set to a true value):
my $sql_splitter = SQL::SplitStatement->new(
keep_empty_statements => 1
);
my @statements = $sql_splitter->split( 'SELECT 1;' );
print 'The SQL code contains ' . scalar(@statements) . ' statements.';
# The SQL code contains 2 statements.
"split_with_placeholders"
• "$sql_splitter->split_with_placeholders( $sql_string )"
It works exactly as the "split" method explained above, except that it returns also a list of integers,
each of which is the number of the placeholders contained in the corresponding atomic statement.
More precisely, its return value is a list of two elements, the first of which is a reference to the list
of the atomic statements exactly as returned by the "split" method, while the second is a reference to
the list of the number of placeholders as explained above.
Here is an example:
# 4 statements (valid SQLite SQL)
my $sql_code = <<'SQL';
CREATE TABLE state (id, name);
INSERT INTO state (id, name) VALUES (?, ?);
CREATE TABLE city (id, name, state_id);
INSERT INTO city (id, name, state_id) VALUES (?, ?, ?)
SQL
my $splitter = SQL::SplitStatement->new;
my ( $statements, $placeholders )
= $splitter->split_with_placeholders( $sql_code );
# $placeholders now is: [0, 2, 0, 3]
where the returned $placeholders list(ref) is to be read as follows: the first statement contains 0
placeholders, the second 2, the third 0 and the fourth 3.
The recognized placeholders are:
• questionmark placeholders, represented by the "?" character;
• dollarsignnumbered placeholders, represented by the "$1, $2, ..., $n" strings;
• namedparameters, such as ":foo", ":bar", ":baz" etc.
"keep_terminators"
• "$sql_splitter->keep_terminators"
• "$sql_splitter->keep_terminators( $boolean )"
Getter/setter method for the "keep_terminators" option explained above.
"keep_terminator"
An alias for the "keep_terminators" method explained above.
"keep_extra_spaces"
• "$sql_splitter->keep_extra_spaces"
• "$sql_splitter->keep_extra_spaces( $boolean )"
Getter/setter method for the "keep_extra_spaces" option explained above.
"keep_comments"
• "$sql_splitter->keep_comments"
• "$sql_splitter->keep_comments( $boolean )"
Getter/setter method for the "keep_comments" option explained above.
"keep_empty_statements"
• "$sql_splitter->keep_empty_statements"
• "$sql_splitter->keep_empty_statements( $boolean )"
Getter/setter method for the "keep_empty_statements" option explained above.
"slash_terminates"
• "$sql_splitter->slash_terminates"
• "$sql_splitter->slash_terminates( $boolean )"
Getter/setter method for the "slash_terminates" option explained above.
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