Unable to open sqlcipher db file with knex electron

Question

my approach to creating and using an sqlite3 encrypted database.

1_ create an encrypted db file using the ubuntu package sudo apt-get install sqlcipher.

2_ setting PRAGMA key = 'secret'.

3_ in electron :

const myDBConfig = { 
client: "sqlite3",
connection: {
 filename: __dirname.concat("/../../enc_schema.db")
 },
 pool: {
    afterCreate: function(conn, done) {
        conn.run("PRAGMA KEY = 'secret'");
        done();
    }  
 } 
}
const knex = require('knex')(myDBConfig);

the output is : SQLITE_NOTADB: file is not a database.

was my approach completely wrong or is it fixable ???