SQLite� Commands

This chapter will take you through simple and useful commands used by SQLite programmers. These commands are called SQLite dot commands and exception with these commands is that they should not be terminated by a semi-colon (;).

 

Let’s start with typing a simple sqlite3 command at command prompt which will provide you SQLite command prompt where you will issue various SQLite commands.

 

$sqlite3

SQLite version 3.3.6

Enter “.help” for instructions

sqlite>

For a listing of the available dot commands, you can enter “.help” at any time. For example:

sqlite>.help

Above command will display a list of various important SQLite dot commands, which are as follows:

 

Command                  Description

.backup? DB? FILE         Backup DB (default “main”) to FILE

.bail ON|OFF                 Stop after hitting an error. Default OFF

.databases                    List names and files of attached databases

.dump? TABLE?             Dump the database in an SQL text format. If TABLE specified, only dump tables matching LIKE pattern TABLE.

.echo ON|OFF              Turn command echo on or off

.exit                            Exit SQLite prompt

.explain ON|OFF           Turn output mode suitable for EXPLAIN on or off. With no args, it turns EXPLAIN on.

.header(s) ON|OFF       Turn display of headers on or off

.help                           Show this message

.import FILE TABLE      Import data from FILE into TABLE

.indices? TABLE?          Show names of all indices. If TABLE specified, only show indices for tables matching LIKE pattern TABLE.

.load FILE? ENTRY?      Load an extension library

.log FILE|off               Turn logging on or off. FILE can be stderr/stdout

.mode MODE

 

  • Set output mode where MODE is one of:
  • csv Comma-separated values
  • Column Left-aligned columns.
  • html HTML <table> code
  • insert SQL insert statements for TABLE
  • line One value per line
  • list Values delimited by .separator string
  • tabs Tab-separated values
  • tcl TCL list elements

 

 

 

 

 

 

 

.nullvalue STRING    Print STRING in place of NULL values

.output FILENAME    Send output to FILENAME

.output stdout         Send output to the screen

.print STRING…       Print literal STRING

.prompt MAIN CONTINUE Replace the standard prompts

.quit  Exit SQLite prompt

.read FILENAME  Execute SQL in FILENAME

.schema ?TABLE?    Show the CREATE statements. If TABLE specified, only show tables matching LIKE pattern TABLE

.separator STRING   Change separator used by output mode and .import

.show Show the current values for various settings

.stats ON|OFF   Turn stats on or off

.tables? PATTERN?   List names of tables matching a LIKE pattern

.timeout MS     Try opening locked tables for MS milliseconds

.width NUM NUM     Set column widths for “column” mode

.timer ON|OFF       Turn the CPU timer measurement on or off

 

Let’s try .show command to see default setting for your SQLite command prompt.

sqlite>.show

echo: off

explain: off

headers: off

mode: column

nullvalue: “”

output: stdout

separator: “|”

width:

sqlite>

 

Make sure there is no space in between sqlite> prompt and dot command, otherwise it will not work.

Formatting output

You can use the following sequence of dot commands to format your output the way I have listed down in this tutorial:

sqlite>.header on

sqlite>.mode column

sqlite>.timer on

sqlite>

 

Above setting will produce the output in the following format:

 

ID          NAME        AGE         ADDRESS     SALARY

———-  ———-  ———-  ———-  ———-

1           Paul        32          California 20000.0

2           Allen       25          Texas       15000.0

3           Teddy       23          Norway      20000.0

4           Mark        25          Rich-Mind   65000.0

5           David       27          Texas       85000.0

6           Kim         22          South-Hall 45000.0

7           James       24          Houston     10000.0

 

CPU Time: user 0.000000 sys 0.000000

The sqlite_master Table

The master table holds the key information about your database tables and it is called sqlite_master. You can see its schema as follows:

sqlite>.schema sqlite_master

This will produce the following result:

CREATE TABLE sqlite_master

type text,

name text,

tbl_name text,

rootpage integer,

sql text

);

 

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