BBC (British Broadcasting Corporation) > SQL-Shell-1.14 > SQL::Shell

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Module Version: 1.14   Source  

NAME ^

SQL::Shell - command interpreter for DBI shells

SYNOPSIS ^

        use SQL::Shell;
        
        #Initialise and configure
        my $sqlsh = new SQL::Shell(\%settings);
        $sqlsh->set($setting, $new_value);
        $value = $sqlsh->get($setting);
        
        #Interpret commands
        $sqlsh->execute_command($command);
        $sqlsh->run_script($filename);

DESCRIPTION ^

SQL::Shell is a command-interpreter API for building shells and batch scripts. A command-line interface with readline support - sqlsh.pl - is included as part of the CPAN distribution. See <SQL::Shell::Manual> for a user guide.

SQL::Shell offers features similar to the mysql or sql*plus client programs but is database independent. The default command syntax is arguably more user-friendly than dbish not requiring any go, do or slashes to fire SQL statements at the database.

Features include:

You can also install custom commands, rendering formats and command history mechanisms. All the commands run by the interpreter are available via the API so if you don't like the default command syntax you can replace the command regexes with your own.

It's been developed and used in anger with Oracle and mysql but should work with any database with a DBD:: driver.

METHODS ^

$sqlsh = new SQL::Shell(\%settings);

Constructs a new object and initialises it with a set of settings. See "SETTINGS" for a complete list.

$sqlsh->set($setting, $new_value)

Changes a setting once the object has been constructed. See "SETTINGS" for a complete list.

$value = $sqlsh->get($setting)

Fetches a setting. See "SETTINGS" for a complete list.

Commands

$sqlsh->execute_cmd($command)

Executes a command ($command is a string).

Returns 1 if the command was successful. Returns 0 if the command was unsuccessful.

$sqlsh->run_script($filename)

Executes a sequence of commands in a file. Dies if there is a problem.

$sqlsh->install_cmds(\%additional_commands)

%additional_commands should contain a mapping of regex to coderef. See "INSTALLING CUSTOM COMMANDS" for more information.

$sqlsh->uninstall_cmds(\@commands)

@additional_commands should contain a list of regexes to remove. If uninstall_cmds is called with no arguments, all commands will be uninstalled.

$sqlsh->set_param($param, $value)

Equivalent to the "set <param> <value>" command. In many cases this will affect the internal settings accessible through the set and get methods.

Renderers

$sqlsh->install_renderers(\%additional_renderers)

%additional_renderers should contain a mapping of renderer name to coderef. See "INSTALLING CUSTOM RENDERERS" for more information.

$sqlsh->uninstall_renderers(\@renderers)

@renderers should contain a list of renderer names to remove. If uninstall_renderers is called with no arguments, all renderers will be uninstalled.

$sqlsh->render_rowset(\@headers, \@data, $table)

Calls the current renderer (writes to STDOUT)

$sqlsh->log_rowset(\@headers, \@data, $table)

Calls the current logger

Database connection

$dsn = $sqlsh->connect($dsn, $user, $pass)

Connects to a DBI datasource. Equivalent to issuing the "connect $dsn $user $pass" command.

$sqlsh->disconnect()

Disconnects if connected. Equivalent to issuing the "disconnect" command.

$bool = $sqlsh->is_connected()

Check if we're connected to the database.

$string = $sqlsh->dsn()

The datasource we're currently connected as - undef if not connected.

History manipulation

$arrayref = $sqlsh->load_history($filename)

Loads a sequence of commands from a file into the command history. Equivalent to "load history from $filename".

$sqlsh->clear_history()

Clears the command history. Equivalent to "clear history".

$sqlsh->save_history($filename, $size)

Saves the command history to a file in a format suitable for load_history and run_script. Equivalent to "save history to $filename", except the maximum number of items can be specified. $size is optional - if not specified defaults to the MaxHistory setting.

$sqlsh->show_history()

Displays the command history. Equivalent to "show history".

Logging

$sqlsh->enable_logging($level, $file)

Enables logging to a file. $level should be all, queries or commands. Equivalent to "log $level $file".

$sqlsh->disable_logging()

Disables logging to a file. Equivalent to "no log".

Querying

$sqlsh->show_drivers()

Outputs a list of database drivers. Equivalent to "show drivers".

$sqlsh->show_datasources($driver)

Outputs a list of datasources for a driver. Equivalent to "show datasources $driver".

$sqlsh->show_dbh($property)

Outputs a property of a database handle. Equivalent to "show \$dbh $property".

$sqlsh->show_schema()

Equivalent to "show schema".

$sqlsh->show_tables()

Displays a list of tables with row counts. Equivalent to "show tables".

$sqlsh->describe($table)

Displays the columns in the table. Equivalent to "describe $table".

$sqlsh->run_query($sql)

Displays the rowset returned by the query. Equivalent to execute_cmd with a select or explain statement.

Modifying data

$sqlsh->do_sql($sql)

Executes a SQL statement that modifies the database. Equivalent to execute_cmd with a DML or DDL statement.

$sqlsh->begin_work()

Starts a transaction. Equivalent to "begin work".

$sqlsh->commit()

Commits a transaction. Equivalent to "commit".

$sqlsh->rollback()

Rolls back a transaction. Equivalent to "rollback".

$sqlsh->wipe_tables()

Blanks all the tables in the database. Will prompt for confirmation if the Interactive setting is enabled. Equivalent to "wipe tables".

Loading and dumping data

$sqlsh->dump_data($source, $filename, $delimiter)

Dumps data from a table or query into a delimited file. $source should either be a table name or a select query. This is equivalent to the "dump data" command.

$sqlsh->load_data($filename, $table, $delimiter, $uri_decode, $charset_from, $charset_to)

Loads data from a delimited file into a database table. $uri_decode is a boolean value - if true the data will be URI-decoded before being inserted. $charset_from and $charset_to are character set names understood by Locale::Recode. This is equivalent to the "load data" command.

$sqlsh->show_charsets()

Lists the character sets supported by the recoding feature of "load data". Equivalent to "show charsets".

CUSTOMISING ^

INSTALLING CUSTOM COMMANDS

The coderef will be passed the $sqlsh object followed by each argument captured by the regex.

        my %additional_commands = (
        qr/^hello from (\.*)/ => sub {
                my ($self, $name) = @_;
                print "hi there $name\n";
        });

To install this:

        $sqlsh->install_cmds(\%additional_commands)

Then in sqlsh:

        > hello from John
        hi there John

INSTALLING CUSTOM RENDERERS

Renderers are coderefs which are passed the following arguments:

        $sqlsh - the SQL::Shell object
        $fh - the filehandle to render to
        $headers - an arrayref of column headings
        $data - an arrayref of arrays containing the data (row major)
        $table - the name of the table being rendered (not defined in all contexts)

Here's an example to render data in CSV format:

        sub my_renderer {
                my ($sqlsh, $fh, $headers, $data, $table) = @_;
                my $delim = ",";
                print $fh "#Dump of $table" if($table); #Assuming our CSV format support #-style comments
                print $fh join($delim, @$headers)."\n";
                foreach my $row (@$data)
                {       
                        print $fh join($delim, @$row)."\n";
                }               
        }

To install this:

        $sqlsh->install_renderers({'csv' => \&my_renderer});

Then in sqlsh:

        > set display-mode csv

INSTALLING A CUSTOM HISTORY MECHANISM

You can install a custom history recording mechanism by overriding the GetHistory, SetHistory and AddHistory callbacks which should take the following arguments and return values:

$arrayref = $GetHistorySub->()
$SetHistorySub->($arrayref)
$AddHistorySub->($string)

An example:

        my $term = new Term::ReadLine "My Shell";
        my $autohistory = $term->Features()->{autohistory};
        my $sqlsh = new SQL::Shell({
                'GetHistory' => sub {[$term->GetHistory()]}); 
                'SetHistory' => sub {my $history = shift; $term->SetHistory(@$history)});
                'AddHistory' => sub {my $cmd = shift; $term->addhistory($cmd) if !$autohistory});
        });

SETTINGS ^

The following settings can only be set through the constructor or the set method:

        NAME           DESCRIPTION                        DEFAULT
        GetHistory     Callback to fetch history          sub {return \@history}
        SetHistory     Callback to set history            sub {my $n = shift; @history = @$n}
        AddHistory     Callback to add cmd to history     sub {push @history, shift()}
        MaxHistory     Maximum length of history to save  $ENV{HISTSIZE} || $ENV{HISTFILESIZE} || 50
        Interactive    Should SQL::Shell ask questions?   0
        Verbose        Should SQL::Shell print messages?  0
        NULL           How to display null values         NULL

The following are also affected by the set_param method or the "set" command:

        NAME           DESCRIPTION                               DEFAULT
        Renderer       Current renderer for screen               \&_render_box
        Logger         Current renderer for logfile              \&_render_delimited
        Delimiter      Delimiter for delimited format            \t
        Width          Width used for record display             80
        LogLevel       Log what? all|commands|queries            undef
        EscapeStrategy UriEscape|EscapeWhitespace|ShowWhitespace undef
        AutoCommit     Commit each statement                     0
        LongTruncOk    OK to truncate LONG datatypes?            1
        LongReadLen    Amount read from LONG datatypes           512
        MultiLine      Allows multiline sql statements           0

COMMANDS ^

 show drivers
 show datasources <driver>
 connect <dsn> [<user> <pass>] - connect to DBI DSN
 disconnect - disconnect from the DB
 
 show tables - display a list of tables
 show schema - display the entire schema
 desc <table> - display schema of table
 
 show $dbh <attribute> - show a database handle object.
        some examples:
                show $dbh Name
                show $dbh LongReadLen
                show $dbh mysql_serverinfo (mysql only)
 
 set display-mode delimited|spaced|box|record|sql|xml - query display mode
 set log-mode delimited|spaced|box|record|sql|xml - set the query log mode
 set delimiter <delim> - set the column delimiter (default is tab)
 set escape show-whitespace|escape-whitespace|uri-escape|off
        - show-whitespace is just for looking at
        - escape-whitespace is compatible with enter-whitespace
        - uri-escape is compatible with uri-decode (load command)
 set enter-whitespace on|off - allow \r \n and \t in SQL statements
 set uri-encode on|off - allow all non ascii characters to be escaped
 set auto-commit on|off - commit after every statement (default is OFF)
 set longtruncok on|off - See DBI/LongTruncOk  (default is on)
 set longreadlen <int>  - See DBI/LongReadLen  (default is 512)
 set multiline on|off - multiline statements ending in ; (default is off)
 set tracing on|off|deep - debug sqlsh using Log::Trace (default is off)
 
 log (queries|commands|all) <filename> - start logging to <filename>
 no log - stop logging
 
 select ...
 insert ...
 update ...
 create ...
 alter ...
 drop ...
 grant ...
 revoke ...
 begin_work
 commit
 rollback
 
 load <file> into <table> (delimited by foo) (uri-decode) (from bar to baz) 
  - load delimited data from a file
  - use uri-decode if file includes uri-encoded data
  - from, to can take character set to recode data e.g. from CP1252 to UTF-8
 show charsets - display available character sets
 dump <table> into <file> (delimited by foo) - dump delimited data
 dump <sql> into <file> (delimited by foo) - dump delimited data
 dump all tables into <directory> (delimited by foo) - dump delimited data
 wipe tables - remove all data from DB (leaving tables empty)
 
 show history - display command history
 clear history - erases the command history
 save history to <file> - saves the command history
 load history from <file> - loads the command history
 execute <file> - run a set of SQL or sqlsh commands from a file

VERSION ^

$Revision: 1.14 $ on $Date: 2006/12/05 14:31:33 $ by $Author: andreww $

AUTHOR ^

John Alden with contributions by Simon Flack and Simon Stevenson <cpan _at_ bbc _dot_ co _dot_ uk>

COPYRIGHT ^

(c) BBC 2006. This program is free software; you can redistribute it and/or modify it under the GNU GPL.

See the file COPYING in this distribution, or http://www.gnu.org/licenses/gpl.txt

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