Laravel uses wrong primary key updating mysql - mysql

Question

I set a custom string typed primary key in Laravel 6.x, calling
$node=Node::create() is fine, but when calling $node->save() later to update, it uses where ‘instanceId’=0 to match the primary key, which throw an exception with MySQL 1292 error.
For table schema (migrate):
public function up()
{
Schema::create('nodes', function (Blueprint $table) {
$table->string('instanceId')->primary();
$table->string('regionId')->nullable();
$table->string('privateIp')->unique()->nullable();
$table->string('publicIp')->unique()->nullable();
$table->string('dnsRecordId')->unique()->nullable();
$table->unsignedTinyInteger('status')->default(0);
$table->unsignedInteger('userId');
$table->timestamps();
});
}
For model definition:
/**
* The primary key associated with the table.
*
* #var string
*/
protected $primaryKey = 'instanceId';
/**
* The attributes that are mass assignable.
*
* #var array
*/
protected $fillable = [
'instanceId',
'regionId',
'privateIp',
'publicIp',
'dnsRecordId',
'status',
'userId',
];
/**
* The attributes that should be casted to native types.
*
* #var array
*/
protected $casts = [
'userId' => 'integer',
];

Answer 1

Looks like you didn't set the value of instanceId before calling $node->save().
so it looks like $node->instanceId was null and since instanceId is a primary key it can't be null.
To prevent such issue, you need to set the value of instanceId before saving it or else you can set the default random value of the instanceId in the createSchema.
$node->instanceId = str_random(20);
Thanks

Answer 2

Thanks to lagbox, this is really a RTFM problem.
When using string primary key $incrementing=false and $keyType=‘string’ are required, otherwise Laravel will assume the primary key is self incrementing integer.