createTable method Null safety

void createTable()

Builds a BlockRepository that will use db for persistence.

It calls createTable to make sure the table exists.

Implementation

void createTable() => db.execute('''
  CREATE TABLE IF NOT EXISTS $table (
    $columnId BLOB PRIMARY KEY NOT NULL,
    $columnVersion INTEGER NOT NULL,
    $columnPreviousHash BLOB,
    $columnTransactionRoot BLOB,
    $columnTimestamp INTEGER);
  ''');