异常:SQLSTATE[23000]:完整性约束冲突:1452无法添加或更新子行:外键约束失败

Question

供应商表

Schema::create('suppliers', function (Blueprint $table) {
$table->id();
$table->string('supplier_name');
});

测试_供应商_表格

Schema::create('test_suppliers', function (Blueprint $table) {
$table->id();
$table->integer('supplier_id')->nullable();
$table->foreign('supplier_id')->references('suppliers')->on('id');
$table->dateTime('started_at')->nullable();
$table->dateTime('finished_at')->nullable();
$table->timestamps();
});

在这里，当我试图插入测试供应商模型时，我遇到了这个问题

foreach ($itest_suppliers_data as $itest_supplier) {
$supplier_name = $arrayhave['supplier_name'];
$supplier_id = Supplier::where('supplier_name', $supplier_name)->pluck('supplier_id');
TestSuppliers::insert([ // noticed that test_suppliers_table is empty
'started_at' => date("Y-m-d H:i:s", time()),
'supplier_id' => $supplier_id,
'finished_at' => date("Y-m-d H:i:s", time()),
]);

Answer 1

供应商表的架构不正确。应该是：

Schema::create('suppliers', function (Blueprint $table) {
$table->id();
$table->string('name');
});

您的下一个问题是，您的$supplier_id变量是一个id集合，而不是单个id。您应该将其更改为：

$supplier_id = Supplier::where('name', $supplier_name)->first()->id;

Answer 2

pluck将返回一个集合。您需要使用value来获得实际值：

foreach ($itest_suppliers_data as $itest_supplier) {
$supplier_name = $arrayhave['supplier_name'];
$supplier_id = Supplier::where('supplier_name', $supplier_name)->value('supplier_id');
TestSuppliers::insert([ // noticed that test_suppliers_table is empty
'started_at' => date("Y-m-d H:i:s", time()),
'supplier_id' => $supplier_id,
'finished_at' => date("Y-m-d H:i:s", time()),
]);

这里value相当于说Supplier::where('supplier_name', $supplier_name)->first()->supplier_id，当然这是假设你知道总会有一个结果。我认为不管怎样，对$supplier_id进行空检查可能是明智的。