数据迁移 一， 使用.dump命令 命令帮助提示 .dump ?TABLE? ... Dump the database in an SQL text format If TABLE specified, only dump tables matching LIKE pattern TABLE. 理解分析： 默认情况下.dump 命令的输出定向到屏幕。如：.dump 如果要将输出重
一， 使用.dump命令
命令帮助提示
.dump ?TABLE? ... Dump the database in an SQL text format
If TABLE specified, only dump tables matching
LIKE pattern TABLE.
理解分析：
默认情况下.dump 命令的输出定向到屏幕。如：.dump
如果要将输出重定向到文件，请使用.dump[filename]命令，此命令将所有的输出重定向到指定的文件中。若要恢复到屏幕的输出，只需要执行.output stdout命令就OK了。
sqlite>.output file.sql
sqlite>.dump
sqlite>.output stdout
注：如果file.sql不存在，将在当前工作目录中创建该文件。如果文件存在，它将被覆盖。
二，准备测试数据：
CREATE TABLE COMPANY(ID INT NOT NULL, NAME VARCHAR(20),AGE INT,ADDRESS VARCHAR(20),SALARY DECIMAL(7,2));
INSERT INTO COMPANY
SELECT 1, 'Paul', 32, 'California' ,20000.0 UNION ALL
SELECT 2, 'Allen', 25, 'Texas' ,15000.0 UNION ALL
SELECT 3, 'Teddy', 23, 'Norway' ,20000.0 UNION ALL
SELECT 4, 'Mark', 25, 'Rich-Mond' ,65000.0 UNION ALL
SELECT 5, 'David', 27, 'Texas' ,85000.0 UNION ALL
SELECT 6, 'Kim', 22, 'South-Hall' ,45000.0 UNION ALL
SELECT 7, 'James', 24, 'Houston' ,10000.0 ;
SELECT * FROM COMPANY;
CREATE TABLE t1(id INT,NAME VARCHAR(20));
INSERT INTO t1 SELECT 1,'a' UNION ALL SELECT 2,'b' UNION ALL SELECT 3,'c';
将低版本的表修改表名为临时表COMPANY_TMP。
ALTER TABLE COMPANY RENAME TO COMPANY_TMP;
三，开始备份操作，在低版本3.6.2上面做备份：
[root@name01 ~]# /usr/bin/sqlite3.bak.3.6.2 tim
SQLite version 3.6.20
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite>
sqlite> .headers on
sqlite> .mode columns
sqlite> .output alltables.sql
sqlite> .dump
sqlite>.exit
四，查看生成的备份文件：
[root@name01 ~]# more alltables.sql
PRAGMA foreign_keys=OFF;
BEGIN TRANSACTION;
CREATE TABLE "COMPANY_TMP"(ID INT NOT NULL, NAME VARCHAR(20),AGE INT,ADDRESS VARCHAR(20),SALARY DECIMAL(7,2));
INSERT INTO "COMPANY_TMP" VALUES(1,'Paul',32,'California',20000);
INSERT INTO "COMPANY_TMP" VALUES(2,'Allen',25,'Texas',15000);
INSERT INTO "COMPANY_TMP" VALUES(3,'Teddy',23,'Norway',20000);
INSERT INTO "COMPANY_TMP" VALUES(4,'Mark',25,'Rich-Mond',65000);
INSERT INTO "COMPANY_TMP" VALUES(5,'David',27,'Texas',85000);
INSERT INTO "COMPANY_TMP" VALUES(6,'Kim',22,'South-Hall',45000);
INSERT INTO "COMPANY_TMP" VALUES(7,'James',24,'Houston',10000);
CREATE TABLE t1(id INT,NAME VARCHAR(20));
INSERT INTO "t1" VALUES(1,'a');
INSERT INTO "t1" VALUES(2,'b');
INSERT INTO "t1" VALUES(3,'c');
COMMIT;
[root@name01 ~]#
看到都是一条条备份成的dml、ddl的sql语句。
五，在高版本3.8.6上面恢复数据
1，在3.8.6上面建立相同的COMPANY表，不过多添加了2个字段IPHONE和LOGIN_DATE，如下所示：
DROP TABLE IF EXISTS COMPANY;
CREATE TABLE COMPANY(
ID INT NOT NULL,
NAME VARCHAR(20),
AGE INT,
ADDRESS VARCHAR(20),
SALARY DECIMAL(7,2),
IPHONE VARCHAR(16)
NOT NULL,LOGIN_DATE DATETIME
);
INSERT INTO COMPANY
SELECT 1, 'Paul', 32, 'California' ,20000.0,'14782121412',DATETIME('NOW') UNION ALL
SELECT 2, 'Allen', 25, 'Texas' ,15000.0,'13982121412',DATETIME('NOW') ;
SELECT * FROM COMPANY;
2， 开始恢复导入原来备份的数据sql脚本
[root@name01 ~]# sqlite3 ti
SQLite VERSION 3.8.6 2014-08-15 11:46:33
Enter ".help" FOR USAGE hints.
sqlite> .headers ON
sqlite> .MODE COLUMNS
sqlite> .READ alltables.sql
sqlite> .TABLE
COMPANY COMPANY_TMP t1
sqlite>
3，在数据迁移从旧临时表迁移到新表之前，查下现有表的数据
sqlite>SELECT * FROM COMPANY;
ID NAME AGE ADDRESS SALARY IPHONE LOGIN_DATE
---------- ---------- ---------- ---------- ---------- ----------- -------------------
1 Paul 32 California 20000 14782121412 2014-08-29 11:14:07
2 Allen 25 Texas 15000 13982121412 2014-08-29 11:14:07
sqlite>
4，开始使用INSERT迁移数据到新添加字段的表COMPANY
sqlite> INSERT INTO COMPANY(ID,NAME,AGE,ADDRESS,SALARY,IPHONE) SELECT ID,NAME,AGE,ADDRESS,SALARY,'' FROM COMPANY_TMP ;
sqlite> SELECT * FROM COMPANY;
ID NAME AGE ADDRESS SALARY IPHONE LOGIN_DATE
---------- ---------- ---------- ---------- ---------- ----------- -------------------
1 Paul 32 California 20000 14782121412 2014-08-29 11:14:07
2 Allen 25 Texas 15000 13982121412 2014-08-29 11:14:07
1 Paul 32 California 20000
2 Allen 25 Texas 15000
3 Teddy 23 Norway 20000
4 Mark 25 Rich-Mond 65000
5 David 27 Texas 85000
6 Kim 22 South-Hall 45000
7 James 24 Houston 10000
sqlite>
看到迁移数据之后的显示，旧表数据已经迁移到新表了。
六，最后删除旧的临时表
sqlite> DROP TABLE IF EXISTS COMPANY_TMP;
sqlite>
至此，整个数据迁移工作顺利结束。
