我是 iPhone 开发的新手。我正在制作一个应用程序，使用 sqlite3 作为数据库。我用 sqlite3 manager 3.9.5 创建了我的表，并在 appdelegete.m 文件中编写了代码复制数据库，并成功复制了数据库。
我在数据库中插入数据并使用主键成功插入，但是当我从数据库访问数据时，它发送 null 并且如果我打开我的数据库并打开我的表，它们不会显示我在表中输入的数据。这是我插入数据并从数据库获取数据的代码。
- (IBAction)addrecord:(id)sender {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:@"ebirthdaydatabase.sqlite"];
if (sqlite3_open([path UTF8String], &database) == SQLITE_OK) {
const char *sqlStatement = "insert into Name(name) VALUES(?)";
sqlite3_stmt *compiledStatement;
if (sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK){
NSLog(@"name.text :%@",name.text);
sqlite3_bind_text(compiledStatement, 1, [name.text UTF8String], -1, SQLITE_TRANSIENT);
// ShowContactsViewController *contact = [[ShowContactsViewController alloc]init];
// contact.username = name.text;
// [contact addarray:contact];
}
if(sqlite3_step(compiledStatement) != SQLITE_DONE ) {
NSLog( @"Error: %s", sqlite3_errmsg(database) );
} else {
NSLog( @"Insert into row id = %lld", sqlite3_last_insert_rowid(database));
}
sqlite3_finalize(compiledStatement);
sqlite3_close(database);
}
sqlite3 *database;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:@"ebirthdaydatabase.sqlite"];
NSLog(@"%@",path);
if (sqlite3_open([path UTF8String], &database) == SQLITE_OK) {
const char *sql = "select name from Name";
sqlite3_stmt *selectstmt;
if(sqlite3_prepare_v2(database, sql, -1, &selectstmt, NULL) == SQLITE_OK) {
while(sqlite3_step(selectstmt) == SQLITE_ROW) {
// NSInteger primaryKey = sqlite3_column_int(selectstmt, 0);
// Coffee *coffeeObj = [[Coffee alloc] initWithPrimaryKey:primaryKey];
ShowContactsViewController *contact=[[ShowContactsViewController alloc]init];
char *localityChars =( char *)sqlite3_column_name(selectstmt, 0);
if (localityChars ==NULL)
contact.username = nil;
else
contact.username = [NSString stringWithUTF8String: localityChars];
//contact.username = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt, 1)];
NSLog(@"%@",username);
[showcontact addObject:contact];
}
}
}