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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? FILE Backup DB (default “main”) to FILE |
| 2 |
.bail ON|OFF Stop after hitting an error. Default OFF |
| 3 |
.databases List 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|OFF Turn command echo on or off |
| 6 |
.exit Exit SQLite prompt |
| 7 |
.explain ON|OFF Turn output mode suitable for EXPLAIN on or off. With no args, it turns EXPLAIN on |
| 8 |
.header(s) ON|OFF Turn display of headers on or off |
| 9 |
.help Show this message |
| 10 |
.import FILE TABLE Import 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|off Turn logging on or off. FILE can be stderr/stdout |
| 14 |
.mode MODE Set output mode where MODE is one of −
|
| 15 |
.nullvalue STRING Print STRING in place of NULL values |
| 16 |
.output FILENAME Send output to FILENAME |
| 17 |
.output stdout Send output to the screen |
| 18 |
.print STRING… Print literal STRING |
| 19 |
.prompt MAIN CONTINUE Replace the standard prompts |
| 20 |
.quit Exit SQLite prompt |
| 21 |
.read FILENAME Execute SQL in FILENAME |
| 22 |
.schema ?TABLE? Show the CREATE statements. If TABLE specified, only show tables matching LIKE pattern TABLE |
| 23 |
.separator STRING Change separator used by output mode and .import |
| 24 |
.show Show the current values for various settings |
| 25 |
.stats ON|OFF Turn stats on or off |
| 26 |
.tables ?PATTERN? List names of tables matching a LIKE pattern |
| 27 |
.timeout MS Try opening locked tables for MS milliseconds |
| 28 |
.width NUM NUM Set column widths for “column” mode |
| 29 |
.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.
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 );
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