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In this part of the SQLite tutorial, we cover the sqlite3 command line tool.

The sqlite3 tool

The sqlite3 tool is a terminal based frontend to the SQLite library that can evaluate queries interactively and display the results in multiple formats. It can also be used within scripts.

On the terminal screen, we see the following prompt of the sqlite3 tool:

$ sqlite3 test.db 
SQLite version 3.7.13 2012-06-11 02:05:22
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> 

The .help command is one of the meta commands of the sqlite3 tool. It lists all meta commands. The .exit and the .quit commands exit the sqlite3 session. We can also use the Ctrl+D key combination to quit sqlite3 . The .databases command shows the attached databases. The .tables command lists the available tables.

Creating a database

The complete SQLite database is stored in a single cross-platform disk file. We use the sqlite3 command line tool to create a new database file.

$ sqlite3 test.db

Here we create a new test.db database. If the file exists, it is opened.

Basic sqlite3 meta commands

Next we describe some of the meta commands of the sqlite3 tool.

sqlite> .tables
Books     Customers   Log       Orders    Testing   
Cars      Friends     Names     Reservations

The .tables command shows the available tables.

sqlite> SELECT * FROM Friends;
1|Jane|F
2|Thomas|M
3|Frank|M
4|Elisabeth|F
5|Mary|F
6|Lucy|F
7|Jack|M

Here we get the output of a SELECT statement. By default, the output mode is line and the separator is | .

sqlite> .separator :
sqlite> SELECT * FROM Friends;
1:Jane:F
2:Thomas:M
3:Frank:M
4:Elisabeth:F
5:Mary:F
6:Lucy:F
7:Jack:M

Here we have used a new colon separator.

There are several other output modes available. The following example shows the column output mode.

sqlite> .mode column
sqlite> .headers on
sqlite> SELECT * FROM Friends;
Id      Name    Sex     
----------  ----------  ----------
1       Jane    F     
2       Thomas    M     
3       Frank     M     
4       Elisabeth   F     
5       Mary    F     
6       Lucy    F     
7       Jack    M  

This example shows how data is formatted in sqlite's column mode. The .headers command has also been used to show column headers. By default, the headers are hidden.

The .width command adjusts the size of the columns. (This meta command is relevant only for tables in the column mode.)

sqlite> SELECT Name, Title FROM Authors NATURAL JOIN Books;
Name     Title   
-----------  ----------
Jane Austen  Emma    
Leo Tolstoy  War and Pe
Joseph Hell  Catch XII 
Charles Dic  David Copp
Joseph Hell  Good as Go
Leo Tolstoy  Anna Karen

The column widths are not wide enough to display all data correctly.

sqlite> .width 15 18
sqlite> SELECT Name, Title FROM Authors NATURAL JOIN Books;
Name       Title       
---------------  ------------------
Jane Austen    Emma        
Leo Tolstoy    War and Peace   
Joseph Heller  Catch XII     
Charles Dickens  David Copperfield 
Joseph Heller  Good as Gold    
Leo Tolstoy    Anna Karenia 

Here we change the column widths. The first column will be 15 characters wide, the second 18.

sqlite> .show
   echo: off
  explain: off
  headers: on
   mode: column
nullvalue: "NULL"
   output: stdout
separator: "|"
  stats: off
  width: 15 18 

The .show command lists various settings. These include the output mode, the separator used in the list mode, and whether the headers are on.

sqlite> .schema Cars
CREATE TABLE Cars(Id INTEGER PRIMARY KEY, Name TEXT, Price INTEGER);

The .schema command shows the structure of the table. It gives the DDL SQL to create the table.

It is possible to change the prompt of the sqlite3 with the .prompt command.

sqlite> .prompt "> " ". "
> SELECT * FROM Cars
. LIMIT 2;
Id      Name    Price   
----------  ----------  ----------
1       Audi    52642   
2       Mercedes  57127   
> 

There are two prompts. One is the main prompt and the other is a continuation prompt. The default main prompt is sqlite> and the default continuation prompt is ...> .

Executing SQL from the shell

We can execute SQL commands from the shell.

$ sqlite3 test.db "SELECT * FROM Cars;"
1|Audi|52642
2|Mercedes|57127
3|Skoda|9000
4|Volvo|29000
5|Bentley|350000
6|Citroen|21000
7|Hummer|41400
8|Volkswagen|21600  

Here we have non-interactively executed a SELECT statement; all cars from the Cars table were selected.

Dumping tables

It is possible to dump tables in SQL format to the disk. This way we can easily save the structure and the data of a database table.

We have the Cars table.

sqlite> SELECT * FROM Cars;
Id      Name    Price   
----------  ----------  ----------
1       Audi    52642   
2       Mercedes  57127   
3       Skoda     9000    
4       Volvo     29000   
5       Bentley   350000  
6       Citroen   21000   
7       Hummer    41400   
8       Volkswagen  21600 

We are going to use the .dump command to dump the table.

sqlite> .dump Cars
PRAGMA foreign_keys=OFF;
BEGIN TRANSACTION;
CREATE TABLE Cars(Id INTEGER PRIMARY KEY, Name TEXT, Price INTEGER);
INSERT INTO "Cars" VALUES(1,'Audi',52642);
INSERT INTO "Cars" VALUES(2,'Mercedes',57127);
INSERT INTO "Cars" VALUES(3,'Skoda',9000);
INSERT INTO "Cars" VALUES(4,'Volvo',29000);
INSERT INTO "Cars" VALUES(5,'Bentley',350000);
INSERT INTO "Cars" VALUES(6,'Citroen',21000);
INSERT INTO "Cars" VALUES(7,'Hummer',41400);
INSERT INTO "Cars" VALUES(8,'Volkswagen',21600);
COMMIT;

The .dump command shows us the SQL necessary to create the Cars table.

sqlite> .output cars2.sql
sqlite> .dump Cars

We can also redirect the output to a file. The .output command will redirect the output to the cars2.sql file.

$ cat cars2.sql 
PRAGMA foreign_keys=OFF;
BEGIN TRANSACTION;
CREATE TABLE Cars(Id INTEGER PRIMARY KEY, Name TEXT, Price INTEGER);
INSERT INTO "Cars" VALUES(1,'Audi',52642);
...

We show the contents of the cars2.sql file with the cat command.

Reading SQL

We can read SQL statements from a file name with the .read command.

sqlite> .tables Cars
Cars
sqlite> DROP TABLE Cars;
sqlite> .tables Cars
sqlite> .read cars.sql
sqlite> .tables Cars
Cars
sqlite> SELECT * FROM Cars WHERE Id=1;
Id      Name    Price   
----------  ----------  ----------
1       Audi    52642   

Here we have executed a series of commands. We drop the table and read it from cars.sql .

The .sqlite_history file

The commands and statements are archived in the .sqlite_history file. The file is located in the home directory.

$ tail -5 ~/.sqlite_history 
SELECT * FROM Cars LIMIT 2;
.help
.tables
.echo ON
SELECT * FROM Cars;

Using the tail command, we show the last five entries.

Resource file

The sqlite3 tool has a resource file called .sqliterc . It is located in the home directory. If there is no such file, we can simply create it. The resouce file can contain meta commands, or regular SQL statements. However, we should avoid using SQL in the file.

$ cat .sqliterc 
.mode column
.header on
.nullvalue NULL  

Here is a simple example of a resource file. It has three meta commands. With a resource file, we do not have to execute meta commands all over again when we start the sqlite3 tool. They will be executed automatically at the start of the tool.

$ sqlite3 test.db 
-- Loading resources from /home/janbodnar/.sqliterc
SQLite version 3.7.7 2011-06-23 19:49:22
Enter ".help" for instructions
Enter SQL statements terminated with a ";"

We have a message saying that the tool loaded resources upon the beginning.

Command line options

The tool has several command line options. They mostly duplicate the meta commands. Note that command line options overwrite the resource file meta commands.

$ sqlite3 --help
Usage: sqlite3 [OPTIONS] FILENAME [SQL]
FILENAME is the name of an SQLite database. A new database is created
if the file does not previously exist.
OPTIONS include:
   -bail        stop after hitting an error
   -batch         force batch I/O
   -column        set output mode to 'column'
   -cmd command     run "command" before reading stdin
   -csv         set output mode to 'csv'
   -echo        print commands before execution
   -init filename     read/process named file
   -[no]header      turn headers on or off
   -help        show this message
   -html        set output mode to HTML
   -interactive     force interactive I/O
   -line        set output mode to 'line'
   -list        set output mode to 'list'
   -nullvalue 'text'  set text string for NULL values
   -separator 'x'     set output field separator (|)
   -stats         print memory stats before each finalize
   -version       show SQLite version
   -vfs NAME      use NAME as the default VFS

The -help options gives us the list of all available options with a brief description.

$ sqlite3 -echo -line -noheader test.db
-- Loading resources from /home/janbodnar/.sqliterc
SQLite version 3.7.13 2012-06-11 02:05:22
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> SELECT * FROM Cars LIMIT 2;
SELECT * FROM Cars LIMIT 2;
   Id = 1
 Name = Audi
Price = 52642

   Id = 2
 Name = Mercedes
Price = 57127

We start the sqlite3 tool with -echo , -line , and -noheader options. The SELECT statement is repeated/echoed after being launched. The ouput is in the line mode and we have no headers displayed.

$ sqlite3 -version
-- Loading resources from /home/janbodnar/.sqliterc
3.7.13 2012-06-11 02:05:22 f5b5a13f7394dc143aa136f1d4faba6839eaa6dc

With the -version option we get the sqlite3's version.

$ sqlite3 -html test.db
-- Loading resources from /home/janbodnar/.sqliterc
SQLite version 3.7.13 2012-06-11 02:05:22
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> SELECT * FROM Cars LIMIT 2;
<TR><TH>Id</TH>
<TH>Name</TH>
<TH>Price</TH>
</TR>
<TR><TD>1</TD>
<TD>Audi</TD>
<TD>52642</TD>
</TR>
<TR><TD>2</TD>
<TD>Mercedes</TD>
<TD>57127</TD>
</TR>

With the -html option, we can output the results as simple HTML tables.

In this part of the SQLite tutorial, we worked with the sqlite3 command line tool. We have described various meta commands, shown how to dump tables, and read SQL from files. We described the sqlite's resource file.