IPhone数据库操作代码例子
//database operation打开数据库 -(BOOL) opendatabase{NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);NSString *documentsDirectory = [paths objectAtIndex:0];NSString *path = [documentsDirectory stringByAppendingPathComponent:@"mydb.sql"];NSFileManager *fileManager = [NSFileManager defaultManager];BOOL find = [fileManager fileExistsAtPath:path];//找到数据库文件mydb.sqlif (find) { NSLog(@"Database file have already existed."); if(sqlite3_open([path UTF8String], &database_) != SQLITE_OK) { sqlite3_close(database_); NSLog(@"Error: open database file."); return NO; } return YES;}if(sqlite3_open([path UTF8String], &database_) == SQLITE_OK) {//bFirstCreate_ = YES; [self createChannelsTable:database_];//在后面实现函数createChannelsTable return YES;} else { sqlite3_close(database_); NSLog(@"Error: open database file."); return NO;}return NO;}创建表- (BOOL) createChannelsTable:(sqlite3*)db{char *sql = "CREATE TABLE reports (id integer primary key,stime text,stitle text,scal text,sruntime text)";sqlite3_stmt *statement;if(sqlite3_prepare_v2(db, sql, -1, &statement, nil) != SQLITE_OK) { NSLog(@"Error: failed to prepare statement:create reports table"); return NO;}int success = sqlite3_step(statement);sqlite3_finalize(statement);if ( success != SQLITE_DONE) { NSLog(@"Error: failed to dehydrate:CREATE TABLE reports"); return NO;}NSLog(@"Create table 'reports' successed.");return YES;}插入表 - (BOOL)insertOneChannel:(NSString*)stime mytitle:(NSString*)stitle mycal:(NSString*)scal myruntime:(NSString*)sruntime{sqlite3_stmt *statement;static char *sql = "INSERT INTO reports (id,stime,stitle,scal,sruntime) VALUES(NULL,?,?,?,?)";//问号的个数要和(cid,title,imageData,imageLen)里面字段的个数匹配，代表未知的值，将在下面将值和字段关联。int success = sqlite3_prepare_v2(database_, sql, -1, &statement, NULL);if (success != SQLITE_OK) { NSLog(@"Error: failed to insert:channels"); return NO;}//这里的数字1，2，3，4代表第几个问号//sqlite3_bind_text(statement, 1, stime, -1, SQLITE_TRANSIENT);char *p = [stime cStringUsingEncoding:1];sqlite3_bind_text(statement, 1, [stime cStringUsingEncoding:1], -1, SQLITE_TRANSIENT);sqlite3_bind_text(statement, 2, [stitle cStringUsingEncoding:1], -1, SQLITE_TRANSIENT);sqlite3_bind_text(statement, 3, [scal cStringUsingEncoding:1], -1, SQLITE_TRANSIENT);sqlite3_bind_text(statement, 4, [sruntime cStringUsingEncoding:1], -1, SQLITE_TRANSIENT);success = sqlite3_step(statement);sqlite3_finalize(statement);if (success == SQLITE_ERROR) { NSLog(@"Error: failed to insert into the database with message."); return NO;}NSLog(@"Insert One Channel#############:id = _");return YES;}查询表- (void) getChannels:(NSMutableArray*)fChannels{sqlite3_stmt *statement = nil;char *sql = "SELECT * FROM reports";if (sqlite3_prepare_v2(database_, sql, -1, &statement, NULL) != SQLITE_OK) { NSLog(@"Error: failed to prepare statement with message:get channels.");}//查询结果集中一条一条的遍历所有的记录，这里的数字对应的是列值。while (sqlite3_step(statement) == SQLITE_ROW) { //char* cid = (char*)sqlite3_column_text(statement, 1); char* stime = (char*)sqlite3_column_text(statement, 1); char* stitle =(char*)sqlite3_column_text(statement, 2); char* scal = (char*)sqlite3_column_text(statement, 3); char* sruntime= (char*)sqlite3_column_text(statement, 4); //NSString *tmp = [NSString stringWithCString:stitle encoding:1]; myreportitem* ri = [[myreportitem alloc] init]; ri.mytime = [NSString stringWithCString:stime encoding:1]; ri.mytitle = [NSString stringWithCString:stitle encoding:1]; ri.mycal = [NSString stringWithCString:scal encoding:1]; ri.myruntime = [NSString stringWithCString:sruntime encoding:1]; [fChannels addObject:ri]; [ri release];}sqlite3_finalize(statement);}删除记录- (void)doClearReport: {NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);NSString *documentsDirectory = [paths objectAtIndex:0];NSString *path = [documentsDirectory stringByAppendingPathComponent:@"mydb.sql"];NSFileManager *fileManager = [NSFileManager defaultManager];BOOL find = [fileManager fileExistsAtPath:path];//找到数据库文件mydb.sqlif (find) { NSLog(@"Database file have already existed."); if(sqlite3_open([path UTF8String], &database_) != SQLITE_OK) { sqlite3_close(database_); NSLog(@"Error: open database file."); return NO; } char *sql = "delete from reports"; sqlite3_stmt *statement; if(sqlite3_prepare_v2(database_, sql, -1, &statement, nil) != SQLITE_OK) { NSLog(@"Error: failed to prepare statement:create reports table"); return NO; } int success = sqlite3_step(statement); sqlite3_finalize(statement); if ( success != SQLITE_DONE) { NSLog(@"Error: failed to dehydrate:delete TABLE reports"); return NO; } NSLog(@"Create table 'reports' successed."); sqlite3_close(database_); }} ?