SQLite 命令

本章将介绍 SQLite 编程人员所使用的简单而有用的命令。这些命令被称为SQLite 的点命令,这些命令的异常并是,他们不被终止分号(;)。

让我们开始键入一个简单的 sqlite3 命令在命令提示符下,将提供 SQLite 的命令提示符,会发出各种SQLite 命令。

$sqlite3
SQLite version 3.3.6
Enter ".help" for instructions
sqlite>

可用的点命令的清单,可以在任何时间”.help” 进入。例如:

sqlite>.help

上面的命令会显示一个列表,各种重要的 SQLite 点命令,如下:

命令 描述
.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

让我们尝试  .show 命令可以看到默认设置SQLite 命令提示符。

sqlite>.show
     echo: off
  explain: off
  headers: off
     mode: column
nullvalue: ""
   output: stdout
separator: "|"
    width:
sqlite>

确保sqlite> 提示符点命令之间没有空格,否则将无法正常工作。

格式化输出

您可以使用下面的序列点命令格式化输出的方式在本教程中,以下已经列出:

sqlite>.header on
sqlite>.mode column
sqlite>.timer on
sqlite>

以上设置将产生以下格式输出:

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

sqlite_master 表格

主表中保存数据库表的关键信息,并它被称为 sqlite_master。可以看到它的模式如下:

sqlite>.schema sqlite_master

这将产生以下结果:

CREATE TABLE sqlite_master (
  type text,
  name text,
  tbl_name text,
  rootpage integer,
  sql text
);

        原文作者:SQLite教程
        原文地址: https://www.yiibai.com/sqlite/sqlite_commands.html
        本文转自网络文章,转载此文章仅为分享知识,如有侵权,请联系博主进行删除。
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