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 with 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” any time. For example −
sqlite>.help
The above command will display a list of various important SQLite dot commands, which are listed in the following table.
| Sr.No. | Command & Description |
|---|---|
| 1 | .backup ?DB? FILEBackup DB (default “main”) to FILE |
| 2 | .bail ON|OFFStop after hitting an error. Default OFF |
| 3 | .databasesList names and files of attached databases |
| 4 | .dump ?TABLE?Dump the database in an SQL text format. If TABLE specified, only dump tables matching LIKE pattern TABLE |
| 5 | .echo ON|OFFTurn command echo on or off |
| 6 | .exitExit SQLite prompt |
| 7 | .explain ON|OFFTurn output mode suitable for EXPLAIN on or off. With no args, it turns EXPLAIN on |
| 8 | .header(s) ON|OFFTurn display of headers on or off |
| 9 | .helpShow this message |
| 10 | .import FILE TABLEImport data from FILE into TABLE |
| 11 | .indices ?TABLE?Show names of all indices. If TABLE specified, only show indices for tables matching LIKE pattern TABLE |
| 12 | .load FILE ?ENTRY?Load an extension library |
| 13 | .log FILE|offTurn logging on or off. FILE can be stderr/stdout |
| 14 | .mode MODESet output mode where MODE is one of −csv − Comma-separated valuescolumn − Left-aligned columns.html − HTML <table> codeinsert − SQL insert statements for TABLEline − One value per linelist − Values delimited by .separator stringtabs − Tab-separated valuestcl − TCL list elements |
| 15 | .nullvalue STRINGPrint STRING in place of NULL values |
| 16 | .output FILENAMESend output to FILENAME |
| 17 | .output stdoutSend output to the screen |
| 18 | .print STRING…Print literal STRING |
| 19 | .prompt MAIN CONTINUEReplace the standard prompts |
| 20 | .quitExit SQLite prompt |
| 21 | .read FILENAMEExecute SQL in FILENAME |
| 22 | .schema ?TABLE?Show the CREATE statements. If TABLE specified, only show tables matching LIKE pattern TABLE |
| 23 | .separator STRINGChange separator used by output mode and .import |
| 24 | .showShow the current values for various settings |
| 25 | .stats ON|OFFTurn stats on or off |
| 26 | .tables ?PATTERN?List names of tables matching a LIKE pattern |
| 27 | .timeout MSTry opening locked tables for MS milliseconds |
| 28 | .width NUM NUMSet column widths for “column” mode |
| 29 | .timer ON|OFFTurn 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.
sqlite>.header on sqlite>.mode column sqlite>.timer on sqlite>
The 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
);