SQLite3 笔记

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sqliteinsert
插入一行:
插入一组:
使用select结果插入
多行插入到新表:
多行插入到新表,一步到位:
非常有用的临时表:
sqliteupdate
更新一条记录:
update注意约束
sqlitedelete
约束:
唯一约束unique
autoincrement
主键约束
域约束:默认值
时间戳默认值
NOTNULL约束
check约束
check约束复杂
外键约束
sqlite
存储类
视图
索引
触发器
视图触发器:可更新的视图
事务
冲突




sqlite insert

查看表结构:

sqlite>.schemafoods
CREATETABLEfoods(
idintegerprimarykey,type_idinteger,nametext);


插入一行:

sqlite>insertintofoods(name,type_id)values('CinnamonBobka',1);

sqlite>insertintofoodsvalues(NULL,1,'BlueberryBobka');

验证:
sqlite>select*fromfoodswherenamelike'%bobka';
idtype_idname
-----------------------------------
101ChocolateBobka
131CinnamonBobka
4131CinnamonBobka
4141BlueberryBobka


插入一组:

sqlite>insertintofoodsvalues(null,(selectidfromfood_typeswherename='Bakery'),'BlackberryBobka');
sqlite>select*fromfoodswherenamelike'%bobka';
idtype_idname
-----------------------------------
101ChocolateBobka
131CinnamonBobka
4131CinnamonBobka
4141BlueberryBobka
4151BlackberryBobk
sqlite>



使用select结果插入

sqlite>insertintofoods
...>selectlast_insert_rowid()+1,type_id,namefromfoodswherename='ChocolateBobka';
sqlite>select*fromfoodswherenamelike'%bobka';
idtype_idname
-----------------------------------
101ChocolateBobka
131CinnamonBobka
4131CinnamonBobka
4141BlueberryBobka
4151BlackberryBobk
4161ChocolateBobka
sqlite>

[注意]:字段个数要匹配,数据类型也要匹配:
否则,失败。
sqlite>.schemafoods
CREATETABLEfoods(
idintegerprimarykey,nametext);
sqlite>insertintofoodsselectlast_insert_rowid()+100,name,type_idfromfoodswherename='ChocolateBobka';
Error:UNIQUEconstraintFailed:foods.id
sqlite>



多行插入到新表:

sqlite>createtablefoods2(idint,type_idint,nametext);
sqlite>insertintofoods2select*fromfoods;
sqlite>selectcount(*)fromfoods2;
count(*)
----------
416
sqlite>



多行插入到新表,一步到位:

sqlite>createtablefoods3asselect*fromfoods;
sqlite>selectcount(*)fromfoods3;
count(*)
----------
416
sqlite>


非常有用的临时表:

sqlite>
createtemptablelistas
selectf.namefood,t.namename,(selectcount(episode_id)fromfoods_episodeswherefood_id=f.id)episodes
fromfoodsf,food_typest
wheref.type_id=t.id;

sqlite>select*fromlist;
foodnameepisodes
------------------------------
BagelsBakery1
Bagels,raBakery2
BavarianCBakery1
BearClawsBakery3
BlackandBakery2
Bread(witBakery1
ButterfingBakery1
CarrotCakBakery1
ChipsAhoyBakery1


使用 create table 的这种形式,自增长字段在新表中创建,索引也不会创建,UNIoUE约束都不会被创建。

插入行时的 unique 约束,如果在定义为 unique 的字段中插入重复值,sqlite 会停止并报错。

sqlite>insertintofoodsvalues(416,'ChocolateBobka');
Error:UNIQUEconstraintFailed:foods.id
sqlite>


sqlite update

更新一条记录:

sqlite>updatefoodssetname='CHOCOLATEBOBKA'wherename='ChocolateBobka';
sqlite>select*fromfoodswherenamelike'CHOCOLATE%';
idtype_idname
-----------------------------------
101CHOCOLATEBOBKA
111ChocolateEclai
121ChocolateCream
2229Chocolates,Box
2239ChocolateChip
2249ChocolateCover
4161CHOCOLATEBOBKA
sqlite>


update 注意 约束

sqlite>.schemafoods
CREATETABLEfoods(
idintegerprimarykey,nametext);
sqlite>

sqlite>updatefoodssetid=11wherename='CHOCOLATEBOBKA';
Error:UNIQUEconstraintFailed:foods.id
sqlite>


sqlite delete


sqlite>deletefromfoodswherename='CHOCOLATEBOBKA';


约束:

唯一约束unique

createtablecontacts(
intintegerprimarykey,nametextnotnullcollatenocase,phonetextnotnulldefault'UNKNOWN',unique(name,phone)
);

insertintocontacts(name,phone)values('Jerry','UNKNOWN');



autoincrement

autoincrement 并不会使用未被使用的数字,而是自动递增,但不会阻挡你自己提供的值


sqlite>createtablemaxed_out(idintegerprimarykeyautoincrement,xtext);
sqlite>insertintomaxed_outvalues(10,'wors');
sqlite>select*frommaxed_out;
idx
--------------------
10wors

sqlite>insertintomaxed_outvalues(9223372036854775807,'lastone');
sqlite>select*frommaxed_out;
idx
--------------------
10wors
9223372036lastone

sqlite>insertintomaxed_outvalues(NULL,'willnotwork');
Error:databaSEOrdiskisfull
sqlite>


主键约束

约束:主键约束primarykey不允许存在同样的

sqlite>createtablepkey(xtext,ytext,primarykey(x,y));
sqlite>insertintopkeyvalues('x','y');
sqlite>insertintopkeyvalues('x','x');
sqlite>selectrowid,x,yfrompkey;
rowidxy
------------------------------
1xy
2xx
sqlite>insertintopkeyvalues('x','x');
Error:UNIQUEconstraintFailed:pkey.x,pkey.y
sqlite>



域约束:默认值

域约束:默认值,NULL,NOTNULL,check,sort

1,default默认值
createtablecontacts(
intintegerprimarykey,phone)
);

sqlite>insertintocontacts(name)values('Tom');
sqlite>select*fromcontacts;
intnamephone
------------------------------
1JerryUNKNOWN
2Jerry021-110
3TomUNKNOWN
sqlite>


时间戳默认值

createtabletimes(
idint,datenotnulldefaultcurrent_date,timenotnulldefaultcurrent_time,timestampnotnulldefaultcurrent_timestamp);

sqlite>insertintotimes(id)values(1);
sqlite>insertintotimes(id)values(2);
sqlite>select*fromtimes;
iddatetimetimestamp
-------------------------------------------------
12017-02-1006:14:302017-02-1006:14:30
22017-02-1006:14:322017-02-1006:14:32
sqlite>



NOT NULL 约束

sqlite>.schemacontacts
CREATETABLEcontacts(
intintegerprimarykey,phone)
);
sqlite>insertintocontacts(phone)values("134-1234-5678");
Error:NOTNULLconstraintFailed:contacts.name
sqlite>


check 约束

createtablecontacts(
idintegerprimarykey,phonetextnotnulldefault'空号',phone),check(length(phone)>=7)
);


check 约束 复杂

check约束复杂
createtablefoo(
xinteger,yintegercheck(y>x),zintegercheck(z>abs(y))
);
sqlite>insertintofoovalues(-2,-1,2);
sqlite>select*fromfoo;
xyz
------------------------------
-2-12
sqlite>updatefoosetz=-3wherez=2;
Error:CHECKconstraintFailed:foo
sqlite>



外键约束

外键约束http://www.sqlite.org/foreignkeys.html
确保foods的type_id已存在于food_types的id中。

CREATETABLEfood_types(
idintegerprimarykey,nametext);


CREATETABLEfoods(
idintegerprimarykey,type_idintegerreferencesfood_types(id)
ondeleterestrict
deferrableinitiallydeferred,nametext);



NOACTION:Configuring"NOACTION"meansjustthat:whenaparentkeyismodifiedordeletedfromthedatabase,nospecialactionistaken.

RESTRICT:The"RESTRICT"actionmeansthattheapplicationisprohibitedfromdeleting(forONDELETERESTRICT)ormodifying(forONUPDATERESTRICT)aparentkeywhenthereexistsoneormorechildkeysmappedtoit.ThedifferencebetweentheeffectofaRESTRICTactionandnormalforeignkeyconstraintenforcementisthattheRESTRICTactionprocessinghappensassoonasthefieldisupdated-notattheendofthecurrentstatementasitwouldwithanimmediateconstraint,orattheendofthecurrenttransactionasitwouldwithadeferredconstraint.Eveniftheforeignkeyconstraintitisattachedtoisdeferred,configuringaRESTRICTactioncausessqlitetoreturnanerrorimmediatelyifaparentkeywithdependentchildkeysisdeletedormodified.

SETNULL:Iftheconfiguredactionis"SETNULL",thenwhenaparentkeyisdeleted(forONDELETESETNULL)ormodified(forONUPDATESETNULL),thechildkeycolumnsofallrowsinthechildtablethatmappedtotheparentkeyaresettocontainsqlNULLvalues.

SETDEFAULT:The"SETDEFAULT"actionsaresimilarto"SETNULL",exceptthateachofthechildkeycolumnsissettocontainthecolumnsdefaultvalueinsteadofNULL.RefertotheCREATETABLEdocumentationfordetailsonhowdefaultvaluesareassignedtotablecolumns.

CASCADE:A"CASCADE"actionpropagatesthedeleteorupdateoperationontheparentkeytoeachdependentchildkey.Foran"ONDELETECASCADE"action,thismeansthateachrowinthechildtablethatwasassociatedwiththedeletedparentrowisalsodeleted.Foran"ONUPDATECASCADE"action,itmeansthatthevaluesstoredineachdependentchildkeyaremodifiedtomatchthenewparentkeyvalues.


4,排序

createtablecontacts(
intintegerprimarykey,phone)
);

collate定义排序规则:
nocase忽略大小写
组合起来就是:'Jerry'与'jerry'在插入的时候会被忽略大小写,然后就是一样的,无法二次插入



sqlite

存储类

存储类	描述
NULL	值是一个NULL值。
INTEGER	值是一个带符号的整数,根据值的大小存储在1、2、3、4、6或8字节中。
REAL	值是一个浮点值,存储为8字节的IEEE浮点数字。
TEXT	值是一个文本字符串,使用数据库编码(UTF-8、UTF-16BE或UTF-16LE)存储。
BLOB	值是一个blob数据,完全根据它的输入存储。

视图

视图即虚拟表,也称为派生表。因为视图的内容来自其他的查询结果。
视图不是基本表,尽管感觉起来与表是一样的。基本表的内容是持久的,视图是动态产生的。


视图的起源:如果需要频繁查此表
selectf.name,ft.name,e.name
fromfoodsf
innerjoinfood_typesftonf.type_id=ft.id
innerjoinfoods_episodesfeonf.id=fe.food_id
innerjoinepisodeSEOnfe.episode_id=e.id;


创建视图:sqlite不支持可更新的视图
createviewdetailsas
selectf.nameasfd,ft.nameastp,e.nameasep,e.seasonasssn
fromfoodsf
innerjoinfood_typesftonf.type_id=ft.id
innerjoinfoods_episodesfeonf.id=fe.food_id
innerjoinepisodeSEOnfe.episode_id=e.id;

sqlite>select*fromdetailslimit10;
fdtpepssn
----------------------------------------
BagelsBakeryTheStrike9
Bagels,raBakeryTheStrike9
Bagels,raBakeryTheMuffin8
BavarianCBakeryTheSoupN7
BearClawsBakeryTheStrong9
BearClawsBakeryTheSniffi5
BearClawsBakeryTheRainco5
BlackandBakeryTheDinner5
BlackandBakeryTheUnders6
Bread(witBakeryTheApolog9
sqlite>


删除视图:
dropviewdetails;



索引

索引:
索引是一种用来在某种条件下加速查询的结构。


创建唯一索引
sqlite>droptablefoo;
sqlite>createtablefoo(idinteger,nametext);
sqlite>createuniqueindexfoo_indexonfoo(id,name);
sqlite>insertintofoo(id,name)values(250,'老王');
sqlite>insertintofoo(id,name)values(11,'张三');
sqlite>insertintofoo(id,'老王');
Error:UNIQUEconstraintFailed:foo.id,foo.name
sqlite>select*fromfoo;
idname
--------------------
250老王
11张三
sqlite>


删除索引:
sqlite>dropindexfoo_index;


创建大小写不敏感索引

sqlite>createindexfoods_name_idxonfoods(namecollatenocase);

sqlite>.indices
foods_name_idx

sqlite>.schemafoods
CREATETABLEfoods(
idintegerprimarykey,nametext);
CREATEINDEXfoods_name_idxonfoods(namecollatenocase);
sqlite>


触发器

当具体的表发生特定的数据库事件时,触发器执行对应的sql命令

未更新的行用old引用,已更新的行用new引用
所有属性都可以用点来引用

createtemptablelog(x);
createtemptriggerfoods_update_logupdateofnameonfoods
begin
insertintologvalues('updatefoods:newname='||new.name);
end;

begin;
updatefoodssetname='JUJYFRUIT'wherename='JujyFruit';
select*fromlog;
rollback;



执行结果:
sqlite>createtemptablelog(x);
sqlite>createtemptriggerfoods_update_logupdateofnameonfoods
...>begin
...>insertintologvalues('updatefoods:newname='||new.name);
...>end;
sqlite>
sqlite>begin;
sqlite>updatefoodssetname='JUJYFRUIT'wherename='JujyFruit';
sqlite>select*fromlog;
x
-------------------------------
updatefoods:newname=JUJYFRUIT
sqlite>rollback;
sqlite>

shell执行结果:
chunli@linux:~/work/sqlite$cattrigger.sql
createtemptablelog(x);
createtemptriggerfoods_update_logupdateofnameonfoods
begin
insertintologvalues('updatefoods:newname='||new.name);
end;

begin;
updatefoodssetname='JUJYFRUIT'wherename='JujyFruit';
select*fromlog;
rollback;

chunli@linux:~/work/sqlite$sqlite3foods.db<trigger.sql
updatefoods:newname=JUJYFRUIT
chunli@linux:~/work/sqlite$


视图触发器:可更新的视图

chunli@linux:~/work/sqlite$cattrigger.sql
--创建视图
createviewfoods_viewas
selectf.idfid,f.namefname,t.idtid,t.nametname
fromfoodsf,food_typest;

--创建触发器
createtriggeron_update_foods_viewinsteadofupdateonfoods_view
foreachrow
begin
updatefoodssetname=new.fnamewhereid=new.fid;
updatefood_typessetname=new.tnamewhereid=new.tid;
end;

--小实验,更新视图的数据,自动同步到基础表
begin;
updatefoods_viewsetfname='乐事薯片',tname='FastFood'wherefid=413;
--查询底层表
select*fromfoodsf,food_typestwheref.type_id=t.idandf.id=413;
rollback;

--查询底层表
select*fromfoodsf,food_typestwheref.type_id=t.idandf.id=413;

dropviewfoods_view;

chunli@linux:~/work/sqlite$sqlite3foods.db<trigger.sql
413|1|乐事薯片|1|FastFood
413|1|Whataburger|1|FastFood
chunli@linux:~/work/sqlite$



事务

sqlite事务:
BEGIN[point]/COMMIT[point]/ROLLBACK[point]

默认情况下:sqlite事务是自动提交,执行成功则提交,执行失败则回滚。

begin事务开始,之后的所有事务都可以取消
commit提交
rollback事务回滚


sqlite>begin;
sqlite>deletefromfoods;
sqlite>selectcount(*)fromfoods;
0
sqlite>rollback;
sqlite>selectcount(*)fromfoods;
414
sqlite>
=======================================================
回滚到事务点:
sqlite>begin;
sqlite>selectcount(*)fromfoods;
414
sqlite>deletefromfoods;
sqlite>selectcount(*)fromfoods;
0
sqlite>savepointpoint1;
sqlite>selectcount(*)fromfood_types;
15
sqlite>deletefromfood_types;
sqlite>selectcount(*)fromfood_types;
0
sqlite>rollbacktopoint1;
sqlite>selectcount(*)fromfood_types;
15
sqlite>rollback;
sqlite>selectcount(*)fromfoods;
414
sqlite>




冲突

冲突解决sqlite提供5种冲突解决方案:
replace违反的记录被删除,以新记录代替之
ignore	违反的记录保持原貌,其它记录继续执行
fail	终止命令,违反之前执行的操作得到保存
abort	终止命令,恢复违反之前执行的修改
rollback终止命令和事务,回滚整个事务

语法:

语句级(可覆盖对象级的冲突解决手段)
insert/update/createor[resolution]table/index[tbl_name/idx_name]……
[resolution]:replace、ignore、fail、abort、rollback

对象级(定义表格时)
createtable/index[tbl_name/idx_name]([field_name][format][constraint]onconflict[resolution]);
[constraint]:unique、notnull……



sqlite>updatefoodssetid=800-id;
Error:UNIQUEconstraintFailed:foods.id

sqlite>updateorabortfoodssetid=800-id;
Error:UNIQUEconstraintFailed:foods.id

sqlite>updateorreplacefoodssetid=800-id;
sqlite>
原文链接:https://www.f2er.com/sqlite/198550.html

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