xcode 无法从 iOS 中的 SQLite 数据库中删除行？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/12702266/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Can't delete row from SQLite database in iOS?
提问by Nitin Gohel
I am using this code to delete row from Sqlite3 Database,but it's not working,insert,update,select query are working fine, but the delete statement is not working in my code
我正在使用此代码从 Sqlite3 数据库中删除行，但它不起作用，插入、更新、选择查询工作正常，但删除语句在我的代码中不起作用
-(void)delete{
str=title.text;
sqlite3_stmt *selectstmt;
if (sqlite3_open([path UTF8String], &database) == SQLITE_OK) {
NSString *deleteSQL = [NSString stringWithFormat: @"delete from ToDo where title=\"%@\"",str];
NSLog(@"%@",deleteSQL);
const char *sql = [deleteSQL UTF8String];
sqlite3_prepare_v2(database,sql, -1, &selectstmt, NULL);
if(sqlite3_prepare_v2(database, sql, -1, &selectstmt, NULL) == SQLITE_OK)
NSLog(@"success");
else
NSAssert1(0, @"Error while creating delete statement. '%s'", sqlite3_errmsg(database));
}
sqlite3_finalize(selectstmt);
sqlite3_close(database);
}
What am I doing wrong?
我究竟做错了什么？
回答by iLearner
Hi take a look at it.
你好，看看吧。
I thing you are doing wrong in passing the parameter.
我认为你在传递参数时做错了。
EDIT:
编辑：
str=title.text;
[self openDatabase];//Logic to open database goes here
sqlite3_stmt *stmt=nil;
BOOL status=FALSE;
NSString *deleteSQL = [NSString stringWithFormat: @"delete from ToDo where title='%@'",str];
NSLog(@"%@",deleteSQL);
const char *sql = [deleteSQL UTF8String];
//const char *sql ="delete from ToDo where title='%@'";
if(sqlite3_prepare_v2(db, sql, -1, &stmt, NULL) == SQLITE_OK)
{
sqlite3_bind_text(stmt, 1, [_testId UTF8String], -1, SQLITE_STATIC);
if(SQLITE_DONE != sqlite3_step(stmt))
{
NSLog(@"Error while Deleting");
}
}
sqlite3_finalize(stmt);
[self closeDatabase];//Logic to close database goes here
回答by Nitin Gohel
you can delete particular recored from sqlite database using below code:-
您可以使用以下代码从 sqlite 数据库中删除特定记录：-
NSDictionary *d =(NSDictionary *) [YourMutableArray objectAtIndex:0];
NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [path objectAtIndex:0];
NSString *dbPath =[documentsDir stringByAppendingPathComponent:@"db.sqlite"];
sqlite3_open([dbPath UTF8String], &database);
if(deleteStmt == nil)
{
NSString *deleteStatementNS = [NSString stringWithFormat:
@"delete from tbl_postoffice where type = '%@'",
urusniqIDentifire];
const char *sql = [deleteStatementNS UTF8String];
//const char *sql ="delete from tbl_todo where type = yourDbfildeRecored";
if(sqlite3_prepare_v2(database, sql, -1, &deleteStmt, NULL) != SQLITE_OK)
NSAssert1(0, @"Error while creating delete statement. '%s'", sqlite3_errmsg(database));
}
//When binding parameters, index starts from 1 and not zero.
sqlite3_bind_text(deleteStmt, 1, [[d valueForKey:@"type"] UTF8String], -1, SQLITE_TRANSIENT);
if (SQLITE_DONE != sqlite3_step(deleteStmt))
NSAssert1(0, @"Error while deleting. '%s'", sqlite3_errmsg(database));
sqlite3_reset(deleteStmt);
hope its Helps for you
希望它对你有帮助
回答by Nuzhat Zari
Yes @jason Coco is correct you have prepared your statement twice and you have not called step also after prepare statement..try calling this after prepare:
是的@jason Coco 是正确的，您已经准备了两次您的语句，并且您还没有在准备语句之后调用 step.. 尝试在准备之后调用它：
if (sqlite3_step(selectstmt) == SQLITE_DONE)
{
NSLog(@"success");
}
