android - Using onUpGrade with multiple versions of App to add columns -

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i have versions 4,5 out in production application. between 4 , 5 added new columns app's database adapter using alter statement: 

  public void onupgrade(sqlitedatabase db, int oldversion, int newversion) {         //add new columns         string alter = "alter table " + database_table + " add column " +                 key_newcolumn_name+ " integer default 0";         db.execsql(alter);  }

so, in next version (version 6) if wanted add new column. if had upgraded version 5, of course delete current onupgrade definition , change add new column.

but, if user upgrading version 4 version 6? if leave both alter table statements, fine them, would create duplicate columns version 5 people? running twice matter newer versions?

my question basically, how around missing columns non upgraded people?

you need make if statement each number

if(oldversion < 5)   ... sql alter statement first new column ...  if(oldversion < 6)   ... next sql alter statement

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