如何在数据库操作中插入更新删除，并将数据库保存在文档目录中

我需要获取数据库和插入更新删除通过查询完成，所以任何类可用于简单的操作

+(void)createEditableCopyOfDatabaseIfNeeded { BOOL success; NSFileManager *fileManager = [NSFileManager defaultManager]; NSError *error; NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentDirectory = [paths objectAtIndex:0]; NSString *writableDBPath = [documentDirectory stringByAppendingPathComponent:@"YOUR DB NAME"]; success = [fileManager fileExistsAtPath:writableDBPath]; if (success) { return; } NSString *defualtDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"YOUR DB NAME"]; success = [fileManager copyItemAtPath:defualtDBPath toPath:writableDBPath error:&error]; if (!success) { UIAlertView *alert = [[UIAlertView alloc]initWithTitle:nil message:@"Database Error!!" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil]; [alert show]; [alert release]; } } 

我需要通过查询完整的操作…

Answer 1

在给定的下面创build文件写在database.h文件中

  #import <Foundation/Foundation.h> #import <sqlite3.h> @interface Database : NSObject { } +(NSString* )getDatabasePath; +(NSMutableArray *)executeQuery:(NSString*)str; +(NSString*)encodedString:(const unsigned char *)ch; +(BOOL)executeScalarQuery:(NSString*)str; @end 

这将在database.m文件中

  #import "Database.h" #import <sqlite3.h> @implementation Database +(NSString* )getDatabasePath{ NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:@"YOURDBNAME"]; return writableDBPath; } +(NSMutableArray *)executeQuery:(NSString*)str { sqlite3_stmt *statement= nil; sqlite3 *database; NSString *strPath = [self getDatabasePath]; NSMutableArray *allDataArray = [[NSMutableArray alloc] init]; if (sqlite3_open([strPath UTF8String],&database) == SQLITE_OK) { if (sqlite3_prepare_v2(database, [str UTF8String], -1, &statement, NULL) == SQLITE_OK) { while (sqlite3_step(statement) == SQLITE_ROW) { NSInteger i = 0; NSInteger iColumnCount = sqlite3_column_count(statement); NSMutableDictionary *dict = [[NSMutableDictionary alloc] init]; while (i< iColumnCount) { NSString *str = [self encodedString:(const unsigned char*)sqlite3_column_text(statement, i)]; NSString *strFieldName = [self encodedString:(const unsigned char*)sqlite3_column_name(statement, i)]; [dict setObject:str forKey:strFieldName]; i++; } [allDataArray addObject:dict]; [dict release]; } } else { NSAssert1(0, @"Error: failed to prepare statement with message '%s'.", sqlite3_errmsg(database)); } sqlite3_finalize(statement); } sqlite3_close(database); return allDataArray; } +(BOOL)executeScalarQuery:(NSString*)str{ sqlite3_stmt *statement= nil; sqlite3 *database; BOOL fRet = NO; NSString *strPath = [self getDatabasePath]; if (sqlite3_open([strPath UTF8String],&database) == SQLITE_OK) { if (sqlite3_prepare_v2(database, [str UTF8String], -1, &statement, NULL) == SQLITE_OK) { if (sqlite3_step(statement) == SQLITE_DONE) fRet =YES; } sqlite3_finalize(statement); } sqlite3_close(database); return fRet; } +(NSString*)encodedString:(const unsigned char *)ch { NSString *retStr; if(ch == nil) retStr = @""; else retStr = [NSString stringWithCString:(char*)ch encoding:NSUTF8StringEncoding]; return retStr; } @end