SQLite数据库C++ API封装

　　在一个项目中需要记录目标路径下所有文件的MD5值，由于SQLite简单易用，选择利用它来记录数据。唯一的一张数据表HistoricalMD5，三个属性Dir（完整路径）、Time（时间）、MD5。SQLite常用的C++ API有：sqlite3_open、sqlite3_prepare、sqlite3_bind_parameter_index、sqlite3_bind_text、sqlite3_column_count、sqlite3_step、sqlite3_finalize、sqlite3_close，为了调用方便，对这些函数做了以下封装。

 

Database.h

#include <string> #include <vector> #include <sqlite3.h>



using namespace std; class Database { public: Database(const char* filename); ~Database(); void insert(string dir, int time, string MD5); void update(string dir, int time, string MD5); void query(vector<vector<string> > &results); private: sqlite3 *database; bool openDB(const char* filename); void createTable(); void createIndex(); void closeDB(); };

 

Database.cpp

View Code

#include "Database.h" #include <iostream> Database::Database(const char* filename) { database = NULL; openDB(filename); createTable(); createIndex(); } Database::~Database() { closeDB(); } bool Database::openDB(const char* filename) { if(sqlite3_open(filename, &database) == SQLITE_OK) return true; return false; } void Database::createTable() { sqlite3_stmt *statement; char* query = "CREATE TABLE IF NOT EXISTS HistoricalMD5 (Dir Text PREMARY KEY UNIQUE, Time INTEGER, MD5 TEXT)"; int rc = sqlite3_prepare(database, query, -1, &statement, 0); if ( rc != SQLITE_OK) exit( -1 ); sqlite3_step(statement); sqlite3_finalize(statement); string error = sqlite3_errmsg(database); if(error != "not an error") cout << query << " " << error << endl; } void Database::createIndex() { sqlite3_stmt *statement; char* query = "CREATE INDEX IF NOT EXISTS idxOnText ON HistoricalMD5(Dir);"; int rc = sqlite3_prepare(database, query, -1, &statement, 0); if ( rc != SQLITE_OK) exit( -1 ); sqlite3_step(statement); sqlite3_finalize(statement); string error = sqlite3_errmsg(database); if(error != "not an error") cout << query << " " << error << endl; } void Database::insert(string dir, int time, string MD5) { sqlite3_stmt *statement; char* query = "INSERT INTO HistoricalMD5 VALUES(@_dir, @_time, @_MD5);"; int rc = sqlite3_prepare(database, query, -1, &statement, 0); if ( rc != SQLITE_OK) exit( -1 ); int idx = -1; idx = sqlite3_bind_parameter_index( statement, "@_dir" ); sqlite3_bind_text( statement, idx, dir.c_str(), -1, SQLITE_STATIC ); idx = sqlite3_bind_parameter_index( statement, "@_time" ); sqlite3_bind_int( statement, idx, time); idx = sqlite3_bind_parameter_index( statement, "@_MD5" ); sqlite3_bind_text( statement, idx, MD5.c_str(), -1, SQLITE_STATIC ); sqlite3_step(statement); sqlite3_finalize(statement); string error = sqlite3_errmsg(database); if(error != "not an error") cout << query << " " << error << endl; } void Database::update(string dir, int time, string MD5) { sqlite3_stmt *statement; char* query = "UPDATE HistoricalMD5 SET time=@_time, MD5= @_MD5 WHERE dir=@_dir;"; int rc = sqlite3_prepare(database, query, -1, &statement, 0); if ( rc != SQLITE_OK) exit( -1 ); int idx = -1; idx = sqlite3_bind_parameter_index( statement, "@_dir" ); sqlite3_bind_text( statement, idx, dir.c_str(), -1, SQLITE_STATIC ); idx = sqlite3_bind_parameter_index( statement, "@_time" ); sqlite3_bind_int( statement, idx, time); idx = sqlite3_bind_parameter_index( statement, "@_MD5" ); sqlite3_bind_text( statement, idx, MD5.c_str(), -1, SQLITE_STATIC ); sqlite3_step(statement); sqlite3_finalize(statement); string error = sqlite3_errmsg(database); if(error != "not an error") cout << query << " " << error << endl; } void Database::query(vector<vector<string> > &results) { sqlite3_stmt *statement; char* query = "SELECT * FROM HistoricalMD5;"; if(sqlite3_prepare(database, query, -1, &statement, 0) == SQLITE_OK) { int cols = sqlite3_column_count(statement); int result = 0; while(true) { result = sqlite3_step(statement); if(result == SQLITE_ROW) { vector<string> values; for(int col = 0; col < cols; col++) { values.push_back((char*)sqlite3_column_text(statement, col)); } results.push_back(values); } else { break; } } sqlite3_finalize(statement); } string error = sqlite3_errmsg(database); if(error != "not an error") cout << query << " " << error << endl; } void Database::closeDB() { sqlite3_close(database); }

 

　　推荐几篇相关技术文章：

1、SQlite数据库的C编程接口　　http://blog.csdn.net/northcan/article/details/7226137

2、SQLite学习手册　　http://www.cnblogs.com/stephen-liu74/archive/2012/01/22/2328757.html

3、更多对SQLite的封装　　http://www.sqlite.org/cvstrac/wiki?p=SqliteWrappers