IOS之数据库的查找，删除，添加，更新

核心提示：const unsigned char *phone = sqlite3_column_text(stmt, 2);int age = sqlite3_column_int(stmt, 3);Person *p = [[Person alloc]initWithName:[NSString stringWithUTF8

const unsigned char *phone = sqlite3_column_text(stmt, 2);
int age = sqlite3_column_int(stmt, 3);

Person *p = [[Person alloc]initWithName:[NSString stringWithUTF8String:(const char *)name] phone:[NSString stringWithUTF8String:(const char *)phone] age:age ID:ID];
[persons addObject:p];
[p release];
}
}
else
{
persons = [[NSMutableArray alloc]init];
}
sqlite3_finalize(stmt);
return [persons autorelease];

}
+(int)count
{
sqlite3 *db = [DB openDB];
sqlite3_stmt *stmt = nil;
int result = sqlite3_prepare_v2(db, "select count(ID) from classDB", -1, &stmt, nil);

if (result == SQLITE_OK)
{
int count = 0;
if (sqlite3_step(stmt))
{
count = sqlite3_column_int(stmt, 0);
}
sqlite3_finalize(stmt);
return count;
}
else
{
sqlite3_finalize(stmt);
return 0;
}
}
+(Person *)findByID:(int)ID
{
sqlite3 *db = [DB openDB];
sqlite3_stmt *stmt = nil;
Person *p = nil;
int result = sqlite3_prepare_v2(db, "select * from classDB where ID = ?", -1, &stmt, nil);
if (result == SQLITE_OK)
{
sqlite3_bind_int(stmt, 1, ID);
if (sqlite3_step(stmt))
{
int ID = sqlite3_column_int(stmt, 0);

const unsigned char *name = sqlite3_column_text(stmt, 1);
const unsigned char *phone = sqlite3_column_text(stmt, 2);
int age = sqlite3_column_int(stmt, 3);

p = [[Person alloc]initWithName:[NSString stringWithUTF8String:(const char *)name] phone:[NSString stringWithUTF8String:(const char *)phone] age:age ID:ID];

}
}
sqlite3_finalize(stmt);
return [p autorelease];


}
+(NSMutableArray *)findByname:(NSString *)name
{

sqlite3 *db = [DB openDB];
sqlite3_stmt *stmt = nil;

int result = sqlite3_prepare(db, "select * from classDB where name = ?", -1, &stmt, nil);
NSMutableArray *persons = nil;
if (result == SQLITE_OK)
{
sqlite3_bind_text(stmt, 1, [name UTF8String], -1, nil);

persons = [[NSMutableArray alloc]init];
while (sqlite3_step(stmt) == SQLITE_ROW)
{
int ID = sqlite3_column_int(stmt, 0);
const unsigned char *name = sqlite3_column_text(stmt, 1);
const unsigned char *phone = sqlite3_column_text(stmt, 2);
int age = sqlite3_column_int(stmt, 3);

Person *p = [[Person alloc]initWithName:[NSString stringWithUTF8String:(const char *)name] phone:[NSString stringWithUTF8String:(const char *)phone] age:age ID:ID];

[persons addObject:p];
[p release];

}

}
else
{
persons = [[NSMutableArray alloc]init];
}
sqlite3_finalize(stmt);
return [persons autorelease];
}
//添加元素
+(void)addName:(NSString *)name phone:(NSString *)phone age:(int)age
{
NSString *str = [NSString stringWithFormat:@"insert into classDB(name,phone,age) values('%@','%@',%d)",name,phone,age];