Function schemaExists

schemaExists(d1: SQLDatabase, table: string): Promise<boolean>
Performs a lightweight check to determine if the expected schema is present in the database.
Parameters
- d1: SQLDatabase
  The D1 database instance to check
- table: string
  The name of the table to check
Returns Promise<boolean>
Promise resolving to true if schema tables exist, false otherwise
Example
```
const hasSchema = await schemaExists(env.DB_NEW_SHARD, "users");
if (!hasSchema) {
    console.log('Creating schema on new shard...');
    await createSchema(env.DB_NEW_SHARD, usersSchema);
}
```
- Defined in src/migrations.ts:206