[转]BDB实例代码

待我称王封你为后i 2022-03-29 13:43 199阅读 0赞

### [实例代码][Link 1] ###

[http://blog.csdn.net/mxzy55560593/article/details/7063965][Link 1]

## BTree读写 ##

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1.  Db db(NULL,DB\_CXX\_NO\_EXCEPTIONS);//环境指针
2.  
3.  //事务指针,数据库类别,访问标志(创建,只读,自动提交事务,线程安全),mode在windows中忽略
4.  if(db.open(NULL,"test.db",NULL,DB\_BTREE,DB\_CREATE|DB\_TRUNCATE,0)!=0)
5.  \{
6.  cout<<"同名数据库存在"<<endl;
7.  \}
8.  
9.  //基本写
10. **int** nKey=1;
11. **char** szBuf\[100\]="愚蠢的人类啊";
12. Dbt key,value;
13. key.set\_data(&nKey);
14. key.set\_size(4);
15. value.set\_data(szBuf);
16. value.set\_size(sizeof(szBuf));
17. if(db.put(NULL,&key,&value,0)!=0)
18. \{
19. cout<<"写入失败"<<endl;
20. \}
21. 
22. //基本读
23. **char** szBufRead\[100\]=\{0\};
24. Dbt readKey,readValue;
25. readKey.set\_data(&nKey);
26. readKey.set\_size(4);
27. readValue.set\_data(szBufRead);
28. readValue.set\_ulen(100);
29. readValue.set\_flags(DB\_DBT\_USERMEM);
30. if(db.get(NULL,&readKey,&readValue,0)!=0)
31. \{
32. cout<<"读取失败"<<endl;
33. \}
34. 
35. cout<<szBufRead<<endl;

## Queue读写 ##

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1.  Db db(NULL,DB\_CXX\_NO\_EXCEPTIONS);//环境指针
2.  
3.  db.set\_re\_len(100);
4.  db.set\_re\_pad(0);
5.  
6.  //事务指针,数据库类别,访问标志(创建,只读,自动提交事务,线程安全),mode在windows中忽略
7.  if(db.open(NULL,"DB\\\\test.db",NULL,DB\_QUEUE,DB\_CREATE|DB\_TRUNCATE,0)!=0)
8.  \{
9.  std::cout<<"同名数据库存在"<<std::endl;
10. \}
11. 
12. //基本写
13. **char** szBuf\[100\]="愚蠢的人类啊";
14. **int** nkey=0;
15. Dbt key(&nkey,sizeof(nkey));
16. Dbt value;
17. value.set\_data(szBuf);
18. value.set\_size(sizeof(szBuf));
19. if(db.put(NULL,&key,&value,DB\_APPEND)!=0)
20. \{
21. cout<<"写入失败"<<endl;
22. \}
23. cout<<"返回的记录号为:"<<\*((**int**\*)key.get\_data())<<endl;

## 游标基本读写删 ##

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1.  Db db(NULL,DB\_CXX\_NO\_EXCEPTIONS);//环境指针
2.  //事务指针,数据库类别,访问标志(创建,只读,自动提交事务,线程安全),mode在windows中忽略
3.  if(db.open(NULL,"test.db",NULL,DB\_BTREE,DB\_CREATE|DB\_TRUNCATE,0)!=0)
4.  \{
5.  cout<<"同名数据库存在"<<endl;
6.  \}
7.  
8.  //基本写
9.  **int** nKey=1;
10. **char** szBuf\[100\]="愚蠢的人类啊";
11. 
12. Dbt key,value;
13. key.set\_data(&nKey);
14. key.set\_size(4);
15. value.set\_data(szBuf);
16. value.set\_size(sizeof(szBuf));
17. 
18. for(**int** i=0;i<100;++i)
19. \{
20. nKey=i;
21. if(db.put(NULL,&key,&value,0)!=0)
22. \{
23. cout<<"写入失败"<<endl;
24. \}
25. \}
26. 
27. //游标读
28. Dbc \*p=0;
29. db.cursor(NULL,&p,0);
30. Dbt key1,value1;
31. while(p->get(&key1,&value1,DB\_NEXT)==0)
32. \{
33. cout<<"键:"<<(\*((**int** \*)key1.get\_data()))<<"值:"<<(**char**\*)(value1.get\_data())<<endl;
34. \}
35. //备注:游标没有函数返回当前有多少个键
36. 
37. //查找
38. nKey=80;
39. key1.set\_data(&nKey);
40. key1.set\_size(sizeof(**int**));
41. p->get(&key1,&value1,DB\_SET);
42. p->del(0);
43. 
44. //游标读
45. Dbc \*p1=0;
46. db.cursor(NULL,&p1,0);
47. while(p1->get(&key1,&value1,DB\_NEXT)==0)
48. \{
49. cout<<"键:"<<(\*((**int** \*)key1.get\_data()))<<"值:"<<(**char**\*)(value1.get\_data())<<endl;
50. \}

## 数据库支持重复记录 ##

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1.  Db db(NULL,DB\_CXX\_NO\_EXCEPTIONS);//环境指针
2.  
3.  db.set\_flags(DB\_DUP);
4.  
5.  //事务指针,数据库类别,访问标志(创建,只读,自动提交事务,线程安全),mode在windows中忽略
6.  if(db.open(NULL,"test.db",NULL,DB\_BTREE,DB\_CREATE|DB\_TRUNCATE,0)!=0)
7.  \{
8.  cout<<"同名数据库存在"<<endl;
9.  \}
10. 
11. //基本写
12. **int** nKey=1;
13. **char** szBuf\[100\]="愚蠢的人类啊";
14. 
15. Dbt key,value;
16. key.set\_data(&nKey);
17. key.set\_size(4);
18. value.set\_data(szBuf);
19. value.set\_size(sizeof(szBuf));
20. 
21. for(**int** i=0;i<5;++i)
22. \{
23. if(db.put(NULL,&key,&value,0)!=0)
24. \{
25. cout<<"写入失败"<<endl;
26. \}
27. \}
28. 
29. //游标读
30. Dbc \*p=0;
31. db.cursor(NULL,&p,0);
32. Dbt key1,value1;
33. while(p->get(&key1,&value1,DB\_NEXT)==0)
34. \{
35. cout<<"键:"<<(\*((**int** \*)key1.get\_data()))<<"值:"<<(**char**\*)(value1.get\_data())<<endl;
36. \}

## 基本环境操作 ##

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1.  DbEnv evn(0);
2.  if(evn.open("DB",DB\_CREATE|DB\_INIT\_MPOOL,0)!=0)
3.  \{
4.  cout<<"打开环境错误"<<endl;
5.  return 0;
6.  \}
7.  Db db(&evn,DB\_CXX\_NO\_EXCEPTIONS);//环境指针
8.  
9.  
10. //事务指针,数据库类别,访问标志(创建,只读,自动提交事务,线程安全),mode在windows中忽略
11. if(db.open(NULL,"test.db",NULL,DB\_BTREE,DB\_CREATE|DB\_TRUNCATE,0)!=0)
12. \{
13. cout<<"同名数据库存在"<<endl;
14. \}

## 游标的覆盖操作 ##

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1.  Db db(NULL,DB\_CXX\_NO\_EXCEPTIONS);
2.  db.set\_flags(DB\_DUP);
3.  if(db.open(NULL,"DB\\\\test.db",NULL,DB\_BTREE,DB\_CREATE|DB\_TRUNCATE,0)!=0)
4.  \{
5.  cout<<"打开错误"<<endl;
6.  return 0;
7.  \}
8.  
9.  **int** nkey=1;
10. **char** szBuf\[100\]="愚蠢的地球人";
11. Dbt key(&nkey,sizeof(**int**));
12. Dbt value(szBuf,strlen(szBuf));
13. 
14. for(**int** i=0;i<5;++i)
15. \{
16. db.put(NULL,&key,&value,0);
17. \}
18. 
19. Dbc \*currsor=0;
20. db.cursor(NULL,&currsor,0);
21. 
22. Dbt key1;
23. Dbt value1;
24. sprintf(szBuf,"愚蠢的火星人");
25. currsor->get(&key1,&value1,DB\_FIRST);
26. currsor->get(&key1,&value1,DB\_NEXT);
27. nkey=100;
28. if(currsor->put(&key,&value,DB\_CURRENT)!=0)
29. \{
30. cout<<"put失败"<<endl;
31. \}
32. currsor->get(&key1,&value1,DB\_FIRST);
33. cout<<\*((**int** \*)key1.get\_data())<<":"<<(**char**\*)value1.get\_data()<<endl;
34. 
35. while(currsor->get(&key1,&value1,DB\_NEXT)==0)
36. \{
37. cout<<\*((**int** \*)key1.get\_data())<<":"<<(**char**\*)value1.get\_data()<<endl;
38. \}

## 二级数据库 没成功 ##

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1.  struct Info
2.  \{
3.  **char** name\[20\];
4.  **int** age;
5.  \};
6.  
7.  **int** Fun(Db \*pSecondary,const Dbt \*key,const Dbt \*value,Dbt \*result)
8.  \{
9.  //result->set\_flags(DB\_DBT\_APPMALLOC);
10. Info \*p=(Info \*)value->get\_data();
11. result->set\_data((void \*)(p->age));
12. result->set\_size(sizeof(**int**));
13. //result->set\_ulen(4);
14. return 0;
15. \};
16. 
17. **int** \_tmain(**int** argc, \_TCHAR\* argv\[\])
18. \{
19. Db dbPrimary(NULL,DB\_CXX\_NO\_EXCEPTIONS);
20. if(dbPrimary.open(NULL,"DB\\\\Primary.db",NULL,DB\_BTREE,DB\_CREATE|DB\_TRUNCATE,0)!=0)
21. \{
22. cout<<"打开错误"<<endl;
23. return 0;
24. \}
25. 
26. Dbt key,value;
27. **int** nID=0;
28. Info info;
29. key.set\_data(&nID);
30. key.set\_size(sizeof(**int**));
31. value.set\_data(&info);
32. value.set\_size(sizeof(Info));
33. 
34. **int** nReturn=0;
35. 
36. nID=100;
37. sprintf(info.name,"张三");
38. info.age=20;
39. nReturn+=dbPrimary.put(NULL,&key,&value,0);
40. 
41. nID=200;
42. sprintf(info.name,"里斯");
43. info.age=10;
44. nReturn+=dbPrimary.put(NULL,&key,&value,0);
45. 
46. nID=300;
47. sprintf(info.name,"周杰伦");
48. info.age=40;
49. nReturn+=dbPrimary.put(NULL,&key,&value,0);
50. 
51. if(nReturn!=0)
52. \{
53. cout<<"出错啦"<<endl;
54. return 0;
55. \}
56. 
57. 
58. Db dbSecondary(NULL,DB\_CXX\_NO\_EXCEPTIONS);
59. if(dbSecondary.open(NULL,"DB\\\\Secondary.db",NULL,DB\_BTREE,DB\_CREATE|DB\_TRUNCATE,0)!=0)
60. \{
61. cout<<"打开错误"<<endl;
62. return 0;
63. \}
64. 
65. if(dbPrimary.associate(NULL,&dbSecondary,Fun,DB\_CREATE)!=0)
66. \{
67. cout<<"associate错误"<<endl;
68. return 0;
69. \}
70. 
71. 
72. /\*Dbc \*pCursor=0;
73. if(dbSecondary.cursor(NULL,&pCursor,0)!=0)
74. \{
75. cout<<"cursor创建错误"<<endl;
76. return 0;
77. \}
78. \*/
79. nID=100;
80. if(dbSecondary.get(NULL,&key,&value,0)==0)
81. \{
82. cout<<((Info \*)value.get\_data())->name<<endl;
83. \}
84. 
85. 
86. /\*Dbt key1;
87. Dbt value1;
88. 
89. nID=20;
90. if(pCursor->get(&key1,&value1,DB\_FIRST|DB\_GET\_BOTH)!=0)
91. \{
92. if(pCursor->get(&key1,&value1,DB\_FIRST)==DB\_NOTFOUND)
93. cout<<"没有元素"<<endl;
94. cout<<"get错误"<<endl;
95. return 0;
96. \}
97. cout<<\*((int \*)key1.get\_data())<<":"<<((Info \*)value1.get\_data())->name<<endl;
98. while(pCursor->get(&key1,&value1,DB\_NEXT)!=0)
99. \{
100. cout<<\*((int \*)key1.get\_data())<<":"<<(char \*)value1.get\_data()<<endl;
101. \}\*/
102. 
103. return 0;
104. \}

## 部分写 ##

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1.  Db dbPrimary(NULL,DB\_CXX\_NO\_EXCEPTIONS);
2.  if(dbPrimary.open(NULL,"DB\\\\Primary.db",NULL,DB\_BTREE,DB\_CREATE|DB\_TRUNCATE,0)!=0)
3.  \{
4.  cout<<"打开错误"<<endl;
5.  return 0;
6.  \}
7.  
8.  Dbt key,value;
9.  **int** nID=0;
10. Info info;
11. key.set\_data(&nID);
12. key.set\_size(sizeof(**int**));
13. value.set\_data(&info);
14. value.set\_size(sizeof(Info));
15. 
16. **int** nReturn=0;
17. 
18. nID=100;
19. sprintf(info.name,"张三");
20. info.age=20;
21. nReturn+=dbPrimary.put(NULL,&key,&value,0);
22. 
23. nID=200;
24. sprintf(info.name,"里斯");
25. info.age=10;
26. nReturn+=dbPrimary.put(NULL,&key,&value,0);
27. 
28. nID=300;
29. sprintf(info.name,"周杰伦");
30. info.age=40;
31. nReturn+=dbPrimary.put(NULL,&key,&value,0);
32. 
33. if(nReturn!=0)
34. \{
35. cout<<"出错啦"<<endl;
36. return 0;
37. \}
38. 
39. nID=200;
40. **char** name\[20\]=\{ "四"\};
41. Dbt bt;
42. bt.set\_flags(DB\_DBT\_PARTIAL);
43. bt.set\_data(name);
44. bt.set\_size(20);
45. bt.set\_doff(0);
46. bt.set\_dlen(20);
47. if(dbPrimary.put(NULL,&key,&bt,NULL)==0)
48. \{
49. cout<<"成功"<<endl;
50. 
51. Dbc \*pCursor=0;
52. dbPrimary.cursor(NULL,&pCursor,0);
53. 
54. Dbt key1,value1;
55. while(pCursor->get(&key1,&value1,DB\_NEXT)==0)
56. \{
57. cout<<\*((**int** \*)(key1.get\_data()))<<":"<<((Info \*)(value1.get\_data()))->name<<":"<<((Info \*)(value1.get\_data()))->age<<endl;
58. \}
59. \}

## 事务 ##

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1.  DbEnv env(0);
2.  env.set\_data\_dir("Database");
3.  env.set\_lg\_dir("Log");
4.  //日志系统木默认是开启的
5.  env.open("Environment",DB\_CREATE|DB\_INIT\_MPOOL|DB\_INIT\_TXN|DB\_INIT\_LOCK|DB\_PRIVATE,0);
6.  
7.  Db dbPrimary(&env,DB\_CXX\_NO\_EXCEPTIONS);
8.  
9.  DbTxn \*pTxn;
10. env.txn\_begin(NULL,&pTxn,0);
11. if(dbPrimary.open(pTxn,"Primary.db",NULL,DB\_BTREE,DB\_CREATE,0)!=0)
12. \{
13. cout<<"打开错误"<<endl;
14. return 0;
15. \}
16. pTxn->commit(0);
17. 
18. Dbt key,value;
19. **int** nID=0;
20. Info info;
21. key.set\_data(&nID);
22. key.set\_size(sizeof(**int**));
23. value.set\_data(&info);
24. value.set\_size(sizeof(Info));
25. 
26. **int** nReturn=0;
27. 
28. nID=100;
29. sprintf(info.name,"张三");
30. info.age=20;
31. 
32. nReturn+=dbPrimary.put(NULL,&key,&value,0);
33. 
34. 
35. nID=200;
36. sprintf(info.name,"里斯");
37. info.age=10;
38. 
39. **int** ntime1=timeGetTime();
40. 
41. for(**int** i=0;i<1000000;++i)
42. \{
43. nID+=1;
44. env.txn\_begin(NULL,&pTxn,0);
45. dbPrimary.put(pTxn,&key,&value,0);
46. pTxn->abort();
47. \}
48. **int** ntime2=timeGetTime();
49. cout<<ntime2-ntime1<<endl;
50. 
51. env.txn\_begin(NULL,&pTxn,0);
52. nID=300;
53. sprintf(info.name,"周杰伦");
54. info.age=40;
55. nReturn+=dbPrimary.put(pTxn,&key,&value,0);
56. pTxn->abort();
57. 
58. if(nReturn!=0)
59. \{
60. cout<<"出错啦"<<endl;
61. return 0;
62. \}
63. 
64. Dbc \*pCursor=0;
65. dbPrimary.cursor(NULL,&pCursor,0);
66. 
67. Dbt key1,value1;
68. while(pCursor->get(&key1,&value1,DB\_NEXT)==0)
69. \{
70. cout<<\*((**int** \*)(key1.get\_data()))<<":"<<((Info \*)(value1.get\_data()))->name<<":"<<((Info \*)(value1.get\_data()))->age<<endl;
71. \}

## 最终方案 ##

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1.  DbEnv env(0);
2.  env.set\_data\_dir("Database");
3.  env.set\_lg\_dir("Log");
4.  
5.  env.set\_cachesize(0,500\*1024\*1024,0);
6.  env.log\_set\_config(DB\_TXN\_NOSYNC,1);
7.  env.set\_lg\_bsize(300\*1024\*1024);
8.  
9.  
10. //日志系统木默认是开启的
11. env.open("Environment",DB\_CREATE|DB\_INIT\_MPOOL|DB\_INIT\_TXN|DB\_INIT\_LOCK|DB\_PRIVATE|DB\_RECOVER,0);
12. 
13. //打开数据库
14. Db dbPrimary(&env,DB\_CXX\_NO\_EXCEPTIONS);
15. DbTxn \*pTxn;
16. env.txn\_begin(NULL,&pTxn,0);
17. if(dbPrimary.open(pTxn,"Primary.db",NULL,DB\_BTREE,DB\_CREATE,0)!=0)
18. \{
19. cout<<"打开错误"<<endl;
20. return 0;
21. \}
22. pTxn->commit(0);
23. 
24. Dbt key,value;
25. **int** nID=0;
26. Info info;
27. key.set\_data(&nID);
28. key.set\_size(sizeof(**int**));
29. value.set\_data(&info);
30. value.set\_size(sizeof(Info));
31. 
32. nID=200;
33. sprintf(info.name,"里斯");
34. info.age=10;
35. 
36. **int** ntime1=timeGetTime();
37. env.txn\_begin(NULL,&pTxn,0);
38. for(**int** i=0;i<20000;++i)
39. \{
40. nID+=1;
41. dbPrimary.put(pTxn,&key,&value,0);
42. \}
43. pTxn->commit(0);
44. **int** ntime2=timeGetTime();
45. cout<<(ntime2-ntime1)/1000<<endl;
46. system("pause");

## 一些配置 ##

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[Link 1]: http://blog.csdn.net/mxzy55560593/article/details/7063965
[view plain]: http://blog.csdn.net/mxzy55560593/article/details/7063965#