Creating Trigger to auto-increment id by sequence in JDBC - sql

Question

I am writing methods through JDBC to create a table and a sequence to recall in a Trigger, I want to set up an id column which auto-increments before every insert on the table. I succeeded in building both the createTable method and the createSequence method in the DAO, but when I run the method to create the Trigger I got the java.sql.SQLException: Missing IN or OUT parameter at index:: 1
public void createTrigger() {
PreparedStatement ps;
StringBuilder queryTrigger = new StringBuilder();
queryTrigger.append("CREATE OR REPLACE TRIGGER ");
queryTrigger.append(Tables.getInstance().getName() + "_INSERTED\n");
queryTrigger.append("BEFORE INSERT ON " + Tabelle.getInstance().getName());
queryTrigger.append("\nFOR EACH ROW\n");
queryTrigger.append("BEGIN\n");
queryTrigger.append("SELECT " + Tables.getInstance().getName() + "SEQ.NEXTVAL\n");
queryTrigger.append("INTO :new.id\n");
queryTrigger.append("FROM dual;\n ");
queryTrigger.append("END;\n");
queryTrigger.append("/\n");
queryTrigger.append("ALTER TRIGGER " +Tabelle.getInstance().getName() + "_INSERTED ENABLE\n");
queryTrigger.append("/\n");
String stringQueryTrigger = queryTrigger.toString();
Connection conn = JDBCUtility.openConnection();
try {
ps = (PreparedStatement) conn.prepareStatement(stringQueryTrigger);
ps.executeUpdate();
ps.close();
} catch(SQLException e) {
e.printStackTrace();
}
JDBCUtility.closeConnection(conn);}
Here instead the creation of the table does actually work even if I don't
write the classic lines with parametrized "?" for the preparedStatement.setString(index, String)
public void createTable(Columns c) {
PreparedStatement ps;
StringBuilder query = new StringBuilder();
query.append("CREATE TABLE " + Tabelle.getInstance().getName() + "(");
query.append(Columns.getInstance().getColumnName() + " ");
query.append(Columns.getInstance().getDataType());
if(Columns.getInstance().isNullOrNot() == true) {
query.append(" NOT NULL");
}
else {
query.append("");
}
if(Columns.getInstance().isPrimaryKeyOrNot() == true) {
query.append(" PRIMARY KEY)");
}
else {
query.append(")");
}
String queryToString = query.toString();
Connection conn = JDBCUtility.openConnection();
try {
ps = (PreparedStatement) conn.prepareStatement(queryToString);
ps.executeUpdate();
ps.close();
} catch(SQLException e) {
e.printStackTrace();
}
JDBCUtility.closeConnection(conn);
}
//EDIT
turns out that is enough to substitute the PreparedStatement with a simple Statement, to get rid of the indexes mechanism and get the DB to accept the query

Answer 1

I would suggest creating an auto-increment sequnce in oracle that can be used for all ids and just add the string id.NextVal to the string query
What I mean is:
Rem in oracle create sequence
CREATE SEQUENCE ID
START BY 1
INCREMENT 1
// in java to execute query
String query = "INSERT INTO TABLE VALUES(ID.NEXTVAL);" ;
//rest of code