Dbo: how to add column?
Added by Vladimir Zibarov over 11 years ago
Hello.
In short, how to add new fields to mapped tables in database
I have a database using Wt::Dbo and Sqlite3 backend. First time db created with:
Wt::Dbo::backend::Sqlite3 sqlite3_(WApplication::instance()->appRoot() + "my.db")
Wt::Dbo::Session session;
session.setConnection(sqlite3);
session.mapClass("MyClass");
session.createTables();
Wt::Dbo::Transaction transaction(session);
try {
session.createTables();
Wt::log("info") << "Database created";
} catch (...) {
Wt::log("info") << "Using existing database";
}
I filled up database with many items of MyClass.
Now I added some new fields to MyClass - dateAdded and lastSeen, and error occured:
[error] "Wt: fatal error: Sqlite3: update ""MyClass"\" set ""version"" = ?, ""role"" = ?, ""name"" = ?, ""dateAdded"" = ?, ""lastSeen"" = ? where ""id"" = ? and ""version"" = ?: no such column: dateAdded\"
How to update database file with this new fields?
Replies (2)
RE: Dbo: how to add column? - Added by Saif Rehman over 11 years ago
You'll have to alter the table using the "ALTER TABLE" SQL Statement and run it by calling Wt::Dbo::Session::execute() once.
Or you can alter the table manually.
RE: Dbo: how to add column? - Added by Vladimir Zibarov over 11 years ago
Thanks a lot!
I added lines:
session.execute("alter table MyClass add column 'dateAdded' 'text'");
session.execute("alter table MyClass add column 'lastSeen' 'text'");
Then executed my programm once and after that commented those lines.