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