• 最简单的数据库sqlite3



    一 sqlite

    简单地说SQLite数据库对应的就是一个文件(一般命名为xxx.db)。可以通过sqlite shell命令行来操作sqlite数据库,也可以在其他的语言中通过api来操作sqlite数据库。sqlite数据库的访问甚至不需要用户名和密码。

    在windows上可以下载:sqlite-shell-win32-x86-3071300.zip , 其他平台可以下载对应的shell命令行。

    帮助:

    d:\sqlite_test>sqlite3.exe test.db
    SQLite version 3.7.13 2012-06-11 02:05:22
    Enter ".help" for instructions
    Enter SQL statements terminated with a ";"
    sqlite> .help
    .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 this program
    .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 ?TABLE?     Set output mode where MODE is one of:
                             csv      Comma-separated values
                             column   Left-aligned columns.  (See .width)
                             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
    .prompt MAIN CONTINUE  Replace the standard prompts
    .quit                  Exit this program
    .read FILENAME         Execute SQL in FILENAME
    .restore ?DB? FILE     Restore content of DB (default "main") from FILE
    .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 ?TABLE?        List names of tables
                             If TABLE specified, only list tables matching
                             LIKE pattern TABLE.
    .timeout MS            Try opening locked tables for MS milliseconds
    .trace FILE|off        Output each SQL statement as it is run
    .vfsname ?AUX?         Print the name of the VFS stack
    .width NUM1 NUM2 ...   Set column widths for "column" mode
    .timer ON|OFF          Turn the CPU timer measurement on or off

    二 使用sqlite

    1)打开或创建sqlite数据库

    d:\sqlite_test>sqlite3.exe test.db
    SQLite version 3.7.13 2012-06-11 02:05:22
    Enter ".help" for instructions
    Enter SQL statements terminated with a ";"
    sqlite> 

    2) 创建表及插入数据

    sqlite> create table mytable(name varchar(10), age smallint);
    sqlite> insert into mytable values("itech", 5);
    sqlite> insert into mytable values("jason", 10);
    sqlite> select * from mytable;
    itech|5
    jason|10

    sqlite> 

    3)查看表及表的schema

    sqlite> .tables
    mytable
    sqlite> .schema mytable
    CREATE TABLE mytable(name varchar(10), age smallint);

    sqlite> 

    4)数据库导出为ascii的sql文件 + 重新导入到新的数据库

    d:\sqlite_test>echo .dump | sqlite3 test.db > test.db.dump 

    d:\sqlite_test>type test.db.dump
    PRAGMA foreign_keys=OFF;
    BEGIN TRANSACTION;
    CREATE TABLE mytable(name varchar(10), age smallint);
    INSERT INTO "mytable" VALUES('itech',5);
    INSERT INTO "mytable" VALUES('jason',10);
    COMMIT;
     
    d:\sqlite_test>type test.db.dump | sqlite3 test2.db
    d:\sqlite_test>sqlite3 test2.db
    SQLite version 3.7.13 2012-06-11 02:05:22
    Enter ".help" for instructions
    Enter SQL statements terminated with a ";"
    sqlite> .tables
    mytable
    sqlite>

    5)格式化输出

    sqlite> .mode column
    sqlite> .header on
    sqlite> select * from mytable;
    name        age
    ----------  ----------
    itech       5
    jason       10

    sqlite> 

    完! 

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  • 原文地址:https://www.cnblogs.com/itech/p/2559269.html
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