编辑: - 这就是我所实施的: -
- (void) Delete_LoginData {
sqlite3 *database;
if(sqlite3_open([self.databasePath UTF8String], &database) == SQLITE_OK)
{
const char *sql = "DELETE FROM Login";
sqlite3_stmt *statement;
if(sqlite3_prepare_v2(database, sql,-1, &statement, NULL) == SQLITE_OK)
{
sqlite3_reset(statement);
}
}
}
我想一次点击删除数据库中的所有行。我实现了以下方法: -
- (void) Delete_LoginData {
sqlite3 *database;
if(sqlite3_open([self.databasePath UTF8String], &database) == SQLITE_OK) {
const char *sql = "DELETE * FROM Login";
sqlite3_stmt *statement;
statement = [self PrepareStatement:sql];
// int a1 = sqlite3_bind_int(statement, 1, 1);
sqlite3_step(statement);
sqlite3_reset(statement);
}
}
-(sqlite3_stmt*) PrepareStatement:(const char *)sql{
// Setup the database object
sqlite3 *database;
// Init the animals Array
// Open the database from the users filessytem
if(sqlite3_open([self.databasePath UTF8String], &database) == SQLITE_OK) {
// Setup the SQL Statement and compile it for faster access
const char *sqlStatement = sql;
sqlite3_stmt *compiledStatement;
if(sqlite3_prepare_v2(database, sqlStatement,-1, &compiledStatement, NULL) == SQLITE_OK) {
//NSLog(@"COMPILED STATEMENT: %@",compiledStatement);
return compiledStatement;
}
}
return nil;
}
但行不通。我要为此语句获得0x0 = [自我准备:sql];在delete_logindata方法中。
如何解决这个问题。有什么解决方案吗?
写const char *sql = "DELETE FROM Login"
;而不是const char *sql = "DELETE * FROM Login";
更改您的const char*sql
const char *sql = "DELETE * FROM Login";
用此
更改上面const char *sql = "DELETE FROM Login";
请更改您的方法:
- (void) Delete_LoginData
{
sqlite3 *database;
if(sqlite3_open([self.databasePath UTF8String], &database) == SQLITE_OK)
{
const char *sql = "DELETE FROM Login";
sqlite3_stmt *statement;
if(sqlite3_prepare_v2(database, sql,-1, &statement, NULL) == SQLITE_OK)
{
sqlite3_step(statement);
}
}
}
在您的代码中,您两次打开数据库。在第二种方法中,您正在打开已经打开的数据库!我不知道这是实际问题,但我建议不要这样做。
我不知道什么是正确的答案。但是我可以建议您此链接http://klanguedoc.hubpages.com/hub/ios-5-sdk-database-intert-pate-delete-delete-with-sqlite-sqlite-and-objective-c-c-c-ch-how----帮助u。