File Coverage

blib/lib/SQL/Shell/Manual.pm

Criterion	Covered	Total	%
statement	3	3	100.0
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subroutine	1	1	100.0
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total	4	4	100.0

package SQL::Shell::Manual;

use vars qw($VERSION);
$VERSION = sprintf"%d.%03d", q$Revision: 1.6 $ =~ /: (\d+)\.(\d+)/;

1;

=head1 NAME

SQL::Shell::Manual - user guide for sql shell

=head1 SYNOPSIS

sqlsh -d DBI:Oracle:IFLDEV -u scott -p tiger

=head1 DESCRIPTION

This is a guide to using sqlsh.  sqlsh is an interactive shell run from the command-line for workling with databases.
It can also be run in "batch mode" taking a list of commands from stdin (using the -i switch) or you can pass a single command to it on the command-line.

=head2 Connecting

Either set a DSN in the environment as DBI_DSN, supply with the -d option or use the connect command:

	unixbox% sqlsh
	unixbox% sqlsh -d DBI:Oracle:IFLDEV -u scott -p tiger

You can also connect from inside sqlsh:

	unixbox% sqlsh
	> connect DBI:Oracle:IFLDEV scott tiger
	DBI:Oracle:IFLDEV> show $dbh Name
	+--------+
	| Name   |
	+--------+
	| IFLDEV |
	+--------+

and disconnect:

	DBI:Oracle:IFLDEV> disconnect
	> show $dbh Name
	Not connected to database.

If you don't supply a password, sqlsh will prompt you:

	unixbox% sqlsh -d DBI:Oracle:IFLDEV -u scott
	Enter password for scott:

You can specify a blank password by passing -p:

	unixbox% sqlsh -d DBI:Oracle:IFLDEV -u guest -p

From within sqlsh you can get a list of DBI drivers:

	unixbox% sqlsh
	> show drivers

	  CSV
	  DBM
	  ExampleP
	  Excel
	  File
	  Multiplex
	  Oracle
	  Proxy
	  SQLite
	  Sponge
	  mysql

and a list of possible data sources for a driver:

	unixbox% sqlsh
	> show datasources Oracle

	  dbi:Oracle:GISCPS
	  dbi:Oracle:IFL1
	  dbi:Oracle:IFLDEV
	  dbi:Oracle:IFLTEST

Common DBI DSNs include:

	DBI:Oracle:
	DBI:mysql:
	DBI:ADO:
	DBI:Excel:file=
	DBI:CSV:f_dir=
	DBI:SQLite:dbname=

=head2 Exploring the schema

=head3 show tables

This lists the tables in your database along with other attributes that may
be provided by your platform and driver:

    DBI:SQLite:dbname=test.db> show tables
    +-----------+-------------+--------------------+--------------+---------+
    | TABLE_CAT | TABLE_SCHEM | TABLE_NAME         | TABLE_TYPE   | REMARKS |
    +-----------+-------------+--------------------+--------------+---------+
    | NULL      | main        | sqlite_master      | SYSTEM TABLE | NULL    |
    | NULL      | temp        | sqlite_temp_master | SYSTEM TABLE | NULL    |
    | NULL      | main        | commands           | TABLE        | NULL    |
    +-----------+-------------+--------------------+--------------+---------+

For some database drivers this may include some system tables.

=head3 show tablecounts

This lists the tables with a rowcount for each:

    DBI:SQLite:dbname=test.db> show tablecounts
    +-----------------------------+------+
    | table                       | rows |
    +-----------------------------+------+
    | "main"."sqlite_master"      | 2    |
    | "temp"."sqlite_temp_master" | 0    |
    | "main"."commands"           | 12   |
    +-----------------------------+------+

For some database drivers this may include some system tables. This
command does a C on every table in your database.  You
may not want to do this on databases with large numbers of tables, and/or
tables with large numbers of rows.

=head3 show catalogs

If your platform supports it, this shows a listing of available database
catalogs.

    DBI:ODBC:localdb> show catalogs
    +----------------+
    | TABLE_CAT      |
    +----------------+
    | AdventureWorks |
    | master         |
    | msdb           |
    | tempdb         |
    +----------------+

=head3 show schemas

This command will list the schemas available in your database.  Note that
this is different from C (singular), which shows table
descriptions for every table in your schema (see below).

    DBI:SQLite:dbname=test.db> show schemas
    +-------------+
    | TABLE_SCHEM |
    +-------------+
    | main        |
    | temp        |
    +-------------+

=head3 show tabletypes

List the available table-types in your database.

    DBI:SQLite:dbname=test.db> show tabletypes
    +-----------------+
    | TABLE_TYPE      |
    +-----------------+
    | LOCAL TEMPORARY |
    | SYSTEM TABLE    |
    | TABLE           |
    | VIEW            |
    +-----------------+

=head3 desc

Lists the columns in a table:

	DBI:Oracle:IFLDEV> desc commands
	+-------------+----------------+------+
	| Field       | Type           | Null |
	+-------------+----------------+------+
	| COMMAND     | VARCHAR2(200)  | YES  |
	| DESCRIPTION | VARCHAR2(1020) | YES  |
	+-------------+----------------+------+

=head3 show schema

Lists the columns in a table, for each table in the schema:

	DBI:Oracle:IFLDEV> show schema

	schema dump
	COMMANDS:
	+-------------+----------------+------+
	| Field       | Type           | Null |
	+-------------+----------------+------+
	| COMMAND     | VARCHAR2(200)  | YES  |
	| DESCRIPTION | VARCHAR2(1020) | YES  |
	+-------------+----------------+------+

=head2 Current shell settings (show settings)

To list some C internal settings:

    DBI:SQLite:dbname=test.db> show settings
    +------------------+-------+
    | PARAMETER        | VALUE |
    +------------------+-------+
    | auto-commit      | on    |
    | delimiter        | \t    |
    | enter-whitespace |       |
    | escape           | off   |
    | longreadlen      | 512   |
    | longtruncok      | on    |
    | multiline        | off   |
    | verbose          | on    |
    | width            | 80    |
    +------------------+-------+

Note that not all settings are yet included in this output.

=head2 Querying the database

	DBI:SQLite:dbname=test.db> select * from commands
	+------------------+--------------------------------------------------------------+
	| command          | desc                                                         |
	+------------------+--------------------------------------------------------------+
	| show drivers     | Displays a list of DBI drivers                               |
	| show datasources | Displays a list of available data sources for a driver       |
	| connect          | Connects to a data source                                    |
	| disconnect       | Disconnects from a data source                               |
	| show tables      | List the tables in the schema                                |
	| show tablecounts | List the tables in the schema with a rowcount for each table |
	| show schema      | Lists the columns in each table in the schema                |
	| desc             | List the columns in a table                                  |
	| set              | Set a parameter                                              |
	| help             | Displays sqlsh help in your $PAGER                           |
	| reload           | Reloads sqlsh                                                |
	| exit             | Quits sqlsh                                                  |
	+------------------+--------------------------------------------------------------+

=head3 BLOB values

You can control the amount of BLOB data fetched by setting the C parameter.


	DBI:Oracle:IFLDEV> set longreadlen 4096
	LongReadLen set to '4096'

	DBI:Oracle:IFLDEV> show $dbh LongReadLen
	+-------------+
	| LongReadLen |
	+-------------+
	| 4096        |
	+-------------+

 Note that the C parameter should also be set (it is by default):

	DBI:Oracle:IFLDEV> show $dbh LongTruncOk
	+-------------+
	| LongTruncOk |
	+-------------+
	| 1           |
	+-------------+


=head3 Values containing non-word characters

Suppose we have values in our database which contain whitespace characters (e.g. tabs):

	DBI:Oracle:IFLDEV> set enter-whitespace on
	Whitespace may be entered as \n, \r and \t

	DBI:Oracle:IFLDEV> insert into commands(command,description) values('test', 'one\ttwo')
	INSERT commands: 1 rows affected

When we query the table we see these as literal values:

	DBI:Oracle:IFLDEV> select * from commands
	+---------+-------------+
	| COMMAND | DESCRIPTION |
	+---------+-------------+
	| test    | one two     |
	+---------+-------------+

We can instead chose to display them escaped:

	DBI:Oracle:IFLDEV> set escape show-whitespace
	DBI:Oracle:IFLDEV> select * from commands
	+---------+-------------+
	| COMMAND | DESCRIPTION |
	+---------+-------------+
	| test    | one\ttwo    |
	+---------+-------------+

Alternatively we can use uri-escaping:

	DBI:Oracle:IFLDEV> set escape uri-escape on
	DBI:Oracle:IFLDEV> select * from commands
	+---------+-------------+
	| COMMAND | DESCRIPTION |
	+---------+-------------+
	| test    | one%09two   |
	+---------+-------------+

=head3 Entering multi-line statements

To enable multiline mode:

	DBI:Oracle:IFLDEV> set multiline on

You can then build up statements over multiple lines, ending with a semicolon, e.g.:

	DBI:Oracle:IFLDEV> select
	DBI:Oracle:IFLDEV> count(*)
	DBI:Oracle:IFLDEV> from
	DBI:Oracle:IFLDEV> commands
	DBI:Oracle:IFLDEV> ;
	+----------+
	| COUNT(*) |
	+----------+
	| 12       |
	+----------+

To disable multiline mode, remember you need to end the statement in a semicolon:

	DBI:Oracle:IFLDEV> set multiline off;

=head3 Altering the display mode

The default (C) display mode is similar to that used by the mysql client - it works well for tables of fairly short values.
The C display mode is good for viewing single records:

	DBI:SQLite:dbname=test.db> set display-mode record
	DBI:SQLite:dbname=test.db> select * from commands where command='desc'
	--------------------------------------------------------------------------------
	command | desc
	desc    | List the columns in a table
	--------------------------------------------------------------------------------

The C display mode (despite sounding like a description of sqlsh's author) provides a minimum clutter view of the data.
The C display mode generally looks horrendous but is useful for a quick cut+paste of delimited values.
The C display mode generates insert statements using a $table placeholder for where the data is to be inserted.
The C display mode generates element-only XML which can be parsed into a list of hashes with XML::Simple.

=head2 Altering the database

By default transactions are not automatically committed so you must explicitly commit them:

	DBI:Oracle:IFLDEV> insert into commands(command, description) values ('dump','Writes a table or query results to a delimited file')
	INSERT commands: 1 rows affected

	DBI:Oracle:IFLDEV> commit

and you can roll back mistakes:

	DBI:Oracle:IFLDEV> delete from commands
	DELETE commands: 11 rows affected

	DBI:Oracle:IFLDEV> rollback
	DBI:Oracle:IFLDEV> select count(*) from commands
	+----------+
	| COUNT(*) |
	+----------+
	| 12       |
	+----------+

If you prefer, you can switch autocommit on:

	set autocommit on
	insert ...
	update ...

This is the preferred mode of operation when connecting to some database
platforms like SQL Server.  Depending on the platform, not all commands work
within a "transaction", and some platforms prefer that they be run with
autocommit on. Your mileage may vary.

=head3 Clearing the database

The C command can be used to remove all the data each of the tables in the database:

	DBI:Oracle:IFLDEV> wipe tables
	Wipe all data from:

	  COMMANDS

	Are you sure you want to do this? (type 'yes' if you are) yes

	Wiped all data in database

It prompts you to confirm before anihilating your database.

=head2 The send and recv commands

These commands were added in v1.16. Their purpose is to give the user more
control over how commands are interpreted by the shell before they are sent
to the DB without the need to make the shell identify the commands to determine
whether to expect output or not.  They are intended to deal with
platform-specific variations of SQL syntax that aren't covered by the generic
command-matching process in C.

C is used when you don't expect output from the command, and C is
used for cases where the command provides output, and you'd like it
rendered and displayed, as if it had come from a C.

=head3 Example 1

On IBM Netezza, you can query previously deleted records by giving the
database the following command:

    set show_deleted_records=TRUE

If you try to do that from C, it will tell you that the command is
not recognized, because C has a built-in C command, and it is
trying to match it to what you have typed at the prompt.

The solution is to use the C command to submit the C expression to
the DB without having it intercepted by C:

    send set show_deleted_records=TRUE

=head3 Example 2

On SQL Server there are a number of procedure calls that provide output.  For
instance:

    exec xp_cmdshell 'dir *.exe'

or simply

    xp_cmdshell 'dir *.exe'

While C supports the C command, this is intended to run
commands from a local SQL file.  In this case, C would just reply
that the command is not recognized.  The solution is to use the C
command:

    recv exec xp_cmdshell 'dir *.exe'

or
    recv xp_cmdshell 'dir *.exe'

This will make C submit the exec expression to the DB as if it were
a C command, so that any output is rendered and displayed.

=head3 Example 3

Several database platforms allow giving the C command to query a
different database.  You are in effect switching databases without
disconnecting.  The command looks as follows:

    use MY_DB_NAME

If I give this command while in C, it will not be recognized,
however, I could pass it on to the DB by using C:

    send use MY_DB_NAME

In this case we type C instead or C because we don't expect any
output from the C command.

Note that if your DB platform supports the C command, you may also need
a command to tell you which database you're currently using. This is
platform-dependent, but I will provide an example from SQL Server:

    select dbname() as current_database

=head2 Dumping delimited data

C can either be used to dump an entire table:

	dump mytable into export.txt

or the rowset resulting from a query:

	dump select type, count(*) from mytable group by type into histogram.txt delimited by :

An example:

	DBI:SQLite:dbname=test.db> dump commands into commands.csv delimited by ,
	Dumping commands into commands.csv
	Dumped 12 rows into commands.csv

	DBI:SQLite:dbname=test.db> more commands.csv
	command,desc
	show drivers,Displays a list of DBI drivers
	show datasources,Displays a list of available data sources for a driver
	connect,Connects to a data source
	disconnect,Disconnects from a data source
	show tables,List the tables in the schema with a rowcount for each table
	show schema,Lists the columns in each table in the schema
	desc,List the columns in a table
	set,Set a parameter
	help,Displays sqlsh help in your $PAGER
	reload,Reloads sqlsh
	exit,Quits sqlsh

You can also dump all the tables in a database into a directory:

	dump all tables into dumpdir/

=head2 Logging

You can chose to log commands:

	log commands logfile.txt

or query results:

	log queries dumpfile.txt

or both:

	log all history.log

=head2 Exporting data as XML

	DBI:Oracle:IFLDEV> set log-mode xml

	DBI:Oracle:IFLDEV> log queries export.xml
	Logging queries to export.xml

	DBI:Oracle:IFLDEV>> select * from commands where command like 'show%'
	+------------------+--------------------------------------------------------------+
	| COMMAND          | DESCRIPTION                                                  |
	+------------------+--------------------------------------------------------------+
	| show drivers     | Displays a list of DBI drivers                               |
	| show datasources | Displays a list of available data sources for a driver       |
	| show tables      | List the tables in the schema                                |
	| show tablecounts | List the tables in the schema with a rowcount for each table |
	| show schema      | Lists the columns in each table in the schema                |
	+------------------+--------------------------------------------------------------+

	DBI:Oracle:IFLDEV>> more export.xml


	                show drivers
	                Displays a list of DBI drivers


	                show datasources
	                Displays a list of available data sources for a driver


	                show tables
	                List the tables in the schema


	                show tablecounts
	                List the tables in the schema with a rowcount for each table


	                show schema
	                Lists the columns in each table in the schema



	DBI:Oracle:IFLDEV>> no log
	Stopped logging queries

=head2 Exporting data as SQL

	DBI:Oracle:IFLDEV> set log-mode sql

	DBI:Oracle:IFLDEV> log queries export.sql
	Logging queries to export.sql

	DBI:Oracle:IFLDEV>> select * from commands where command like 'show%'
	+------------------+--------------------------------------------------------------+
	| COMMAND          | DESCRIPTION                                                  |
	+------------------+--------------------------------------------------------------+
	| show drivers     | Displays a list of DBI drivers                               |
	| show datasources | Displays a list of available data sources for a driver       |
	| show tables      | List the tables in the schema                                |
	| show tablecounts | List the tables in the schema with a rowcount for each table |
	| show schema      | Lists the columns in each table in the schema                |
	+------------------+--------------------------------------------------------------+

	DBI:Oracle:IFLDEV>> more export.sql
	INSERT into $table (COMMAND,DESCRIPTION) VALUES ('show drivers','Displays a list of DBI drivers');
	INSERT into $table (COMMAND,DESCRIPTION) VALUES ('show datasources','Displays a list of available data sources for a driver');
	INSERT into $table (COMMAND,DESCRIPTION) VALUES ('show tables','List the tables in the schema');
	INSERT into $table (COMMAND,DESCRIPTION) VALUES ('show tablecounts','List the tables in the schema with a rowcount for each table');
	INSERT into $table (COMMAND,DESCRIPTION) VALUES ('show schema','Lists the columns in each table in the schema');

	DBI:Oracle:IFLDEV>> no log
	Stopped logging queries

You can then replace $table with the table name you want the INSERT stataments to be issued against:

	unixbox% perl -p -i -e 's/\$table/show_commands/' export.sql

=head2 Loading data

Loading a tab-delimited text file is simple:

	load export.txt into mytable

Here's an example:

	DBI:SQLite:dbname=test.db> create table commands(command varchar(50), desc varchar(255))
	CREATE table commands: 0 rows affected

	DBI:SQLite:dbname=test.db> load commands.tsv into commands
	Loaded 12 rows into commands from commands.tsv

As with C you can change the delimiter character:

	load export.csv into mytable delimited by ,

You can also specify character set translations:

	load export.txt into mytable from CP1252 to UTF-8

if your database engine cannot do the character set conversions itself.
See L for a list of character set names.

=head2 Manipulating the command history

You can dump out the history to a file:

	save history to history.txt

You can also load in a set of commands into the history:

	load history from handy_queries.sql

This can be useful in conjunction with C.
You can clear the history at any time with:

	clear history

and display it with:

	show history

=head2 Running batches of commands

You can execute a sequence of sqlsh commands from a file:

	> execute commands.sqlsh

that might have been generated by C or C.
You can also pipe commands into sqlsh on STDIN if you call it with the C<-i> switch:

	unixbox% sqlsh -d DBI:Oracle:IFLDEV -u scott -p tiger -i < commands.sqlsh

=head1 VERSION

v1.17

=head1 AUTHOR

    John Alden
    Miguel Gualdron

=cut