sqlite3在iPhone应用程序中插入或替换语法问题

Question

我在sqlite3插入或替换语法时收到错误;

我的应用程序崩溃,无法进入prepare_v2语句条件.我的代码如下:

NSString *plquery = @"INSERT OR REPLACE INTO LIST (COUNT, NAME, DATE, IDNUM) VALUES (?, ?, ?, ?) WHERE IDNUM = '";
NSString *update = [plquery stringByAppendingFormat:@"%i%@",[accessID integerValue],@"'"];
NSLog(@"%@",update);

sqlite3_stmt *stmt;
if (sqlite3_prepare_v2(database, [update UTF8String], -1, &stmt, nil)== SQLITE_OK)
{
    NSLog(@"reaches here");
    sqlite3_bind_int(stmt, 1, i);
}
if (sqlite3_step(stmt) != SQLITE_DONE)
NSAssert1(0, @"Error updating table: %s", errorMsg); 

Answer 1

你不能插入和在同一声明中的位置.你有3个选择:

1. 如果要更改已存在的行,请将"插入或替换"更改为"更新".
2. 删除where语句以添加新行.
3. 如果您不确定该行是否存在但是先执行'select'语句,则使用上面的2个选项执行if else.

选项1看起来像:

 NSString * update = [NSString stringWithFormat:@"UPDATE LIST SET COUNT = ?, NAME = ?, DATE = ?, IDNUM = ? WHERE IDNUM = '%i'", [accesID integerValue]];

选项2看起来像:

NSString * update = [NSString stringWithFormat:@"INSERT OR REPLACE INTO LIST (COUNT, NAME, DATE, IDNUM) VALUES (?, ?, ?, ?)"];

选项3看起来像:

NSString * update = [NSString stringWithFormat:@"SELECT * FROM LIST WHERE IDNUM = '%i'", [accessID integerValue]];
sqlite3_stmt *stmt;
int rc = sqlite3_prepare_v2(db, [update UTF8String], -1, &stmt, nil);
if (rc == SQLITE_OK) {
    if (sqlite3_step(stmt) == SQLITE_ROW) {
        update = [NSString stringWithFormat:@"UPDATE LIST SET COUNT = ?, NAME = ?, DATE = ?, IDNUM = ? WHERE IDNUM = '%i'", [accessID integerValue]];
    }
    else{
        update = [NSString stringWithFormat:@"INSERT OR REPLACE INTO LIST (COUNT, NAME, DATE, IDNUM) VALUES (?, ?, ?, ?)"];   
    }
}