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:

CommandDescription
.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-Mond   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
);

Source: tutorialspoint.com


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