我正在开发一个使用 sqlite3 数据库文件的 iphone 应用程序。我正在使用以下代码从 sqlite3 数据库中进行选择;
NSString* dbYolu = [NSString stringWithFormat:@"%@/emhdb3.sqlite3",NSHomeDirectory()];
sqlite3* db;
NSLog(@"%@ dbyolu : ", dbYolu);
if (sqlite3_open([dbYolu UTF8String], &db) == SQLITE_OK)
{
NSString *query = [NSString stringWithFormat: @"SELECT username, mobile FROM peopleto WHERE namesurname=\"%@\"", name.text];
NSLog(@"%@ : query", query);
sqlite3_stmt *stmt;
if (sqlite3_prepare_v2(db, [query UTF8String], -1, &stmt, nil) == SQLITE_OK) // statement stmt returns null and returns SQLITE_OK = FALSE.
{
NSLog(@"stepped in SQLITE_OK is TRUE");
while (sqlite3_step(stmt) == SQLITE_ROW)
{
NSString* ders_kodu = [NSString stringWithUTF8String:(char*)sqlite3_column_text(stmt, 0)];
double not = sqlite3_column_double(stmt, 1);
NSLog(@"%@ : %f", ders_kodu, not);
}
}
else
{
NSLog(@"%@ - but failed", stmt);
}
sqlite3_finalize(stmt);
}
else
NSLog(@"db could not be opened");
它在上面的“sqlite3_prepare_v2(db, [query UTF8String], -1, &stmt, nil) == SQLITE_OK" 点失败。错误是:“错误:没有这样的表:peopleto。但是当我在sql浏览器中运行此查询时,它成功返回了表的内容。我的意思是这个查询是正确的并且可以工作。
顺便说一句,我在 viewLoad 上使用以下代码获取带有路径名的文件
- (void)viewDidLoad
{
NSString *docsDir;
NSArray *dirPaths;
// Get the documents directory
dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = [dirPaths objectAtIndex:0];
// Build the path to the database file
databasePath = [[NSString alloc] initWithString:[docsDir stringByAppendingPathComponent: @"emhdb3.sqlite3"]];
NSLog(@"dbpath : %@", databasePath);
NSFileManager *filemgr = [NSFileManager defaultManager];
if ([filemgr fileExistsAtPath: databasePath ] == NO)
{
const char *dbpath = [databasePath UTF8String];
NSLog(@"db not found");
if (sqlite3_open(dbpath, &contactDB) == SQLITE_OK)
{
NSLog(@"SQLITE_OK is passed");
//.... some codes here, doesn't metter for me because SQLITE_OK = true
} else {
status.text = @"Failed to open/create database";
}
}
else if ([filemgr fileExistsAtPath:databasePath] == YES)
{
NSLog(@"i found the file here : %s",[databasePath UTF8String]);
}
NSLog(@"completed");
[super viewDidLoad];
}
我的项目文件夹中有数据库文件并添加到项目中。我错过了什么?
谢谢
///////
我很抱歉更新我的问题,但 stackoverflow 不允许我添加新的,
请在下面找到我的更新;
这是代码的更新版本:
视图加载部分;
- (void)viewDidLoad
{
[self createEditableCopyOfDatabaseIfNeeded];
NSString *docsDir;
NSArray *dirPaths;
dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = [dirPaths objectAtIndex:0];
databasePath = [[NSString alloc] initWithString:[docsDir stringByAppendingPathComponent:@"emhdb3.sqlite3"]];
NSLog(@"dbpath : %@", databasePath);
NSFileManager *filemgr = [NSFileManager defaultManager];
if ([filemgr fileExistsAtPath: databasePath ] == NO)
{
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &contactDB) == SQLITE_OK)
{
char *errMsg;
const char *sql_stmt = "CREATE TABLE IF NOT EXISTS peopleto (pId INTEGER PRIMARY KEY AUTOINCREMENT, namesurname TEXT, mobile TEXT)";
if (sqlite3_exec(contactDB, sql_stmt, NULL, NULL, &errMsg) != SQLITE_OK)
{
status.text = @"Failed to create table";
}
sqlite3_close(contactDB);
} else {
status.text = @"Failed to open/create database";
}
}
else if ([filemgr fileExistsAtPath:databasePath] == YES)
{
NSLog(@"%s is filepath",[databasePath UTF8String]);
}
NSLog(@"checkpoint 4");
[super viewDidLoad];
}
buraya başka birşey yaz
- (void)createEditableCopyOfDatabaseIfNeeded {
NSLog(@"entered createEditableCopyOfDatabaseIfNeeded");
BOOL success;
NSFileManager *fileManager = [NSFileManager defaultManager];
NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:@"emhdb3.sqlite3"];
success = [fileManager fileExistsAtPath:writableDBPath];
if (success)
{
NSLog(@"success == YES returned");
return;
}
NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"emhdb3.sqlite3"];
success = [fileManager copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error];
if (!success) {
NSLog( @"Failed to create writable database file with message '%@'.", [error localizedDescription]);
}
else{
NSLog(@"checkpoint 2");
}
}
以及执行选择查询的部分;
-(IBAction)findcontact2:(id)sender
{
NSString *dbYolu = databasePath;
sqlite3* db;
NSLog(@"%@ dbyolu : ", dbYolu);
if (sqlite3_open([dbYolu UTF8String], &db) == SQLITE_OK)
{
NSString *query = [NSString stringWithFormat: @"SELECT namesurname, mobile FROM peopleto"]; //any query
NSLog(@"%@ : query", query);
sqlite3_stmt *stmt;
if (sqlite3_prepare_v2(db, [query UTF8String], -1, &stmt, nil) == SQLITE_OK)
{
NSLog(@"SQLITE is OK");
while (sqlite3_step(stmt) == SQLITE_ROW)
{
NSString* ders_kodu = [NSString stringWithUTF8String:(char*)sqlite3_column_text(stmt, 0)];
double not = sqlite3_column_double(stmt, 1);
NSLog(@"%@ : %f", namesurname, mobile);
}
}
else
{
NSLog(@"Error=%s",sqlite3_errmsg(db)); // error message : Error=no such table: peopleto
NSLog(@"%@ - is stmt", stmt); //stmt is null
}
sqlite3_finalize(stmt);
}
else
NSLog(@"could not open the db");
}
正如我上面指出的,错误是 Error=no such table: peopleto and stmt is returned null