UltraLite ActiveX User's Guide
  Understanding UltraLite ActiveX Development
    Working with UltraLite databases

Upgrading your database schema

To modify your existing database structure, use the ApplyFile or ApplyFileWithParms method. In most cases there will be no data loss, but data loss can occur if columns are deleted or if the data type for a column is changed to an incompatible type.

For more information about these methods, see ApplyFile method and ApplyFileWithParms method.

The following code fragment connects to a database and applies a new schema file using the ApplyFile method.

For more information about connecting to a database, see Connecting to an UltraLite database.

' eMbedded Visual Basic
Dim db As ULDatabaseManager
Dim conn As ULConnection
Set db = CreateObject("UltraLite.ULDatabaseManager")
Set conn = db.OpenConnection("dbf = \My Documents\mydb.udb")
if ( conn.Schema.TableCount = 0 ) then
  conn.Schema.ApplyFile("\My Documents\myschema.usm")
end if

// JScript
var db;
var conn;
db = new ActiveXObject("UltraLite.ULDatabaseManager");
conn = db.OpenConnection("dbf = \\My Documents\\mydb.udb");
if ( conn.Schema.TableCount == 0 ) {
  conn.Schema.ApplyFile("\\My Documents\\myschema.usm");
}