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Neo4j Graph Database Fundamentals · Pelajaran

Memperbarui dan Menghapus Data Graf

Pelajari cara mengubah node dan relasi yang ada menggunakan SET dan REMOVE, serta menghapus data dengan aman menggunakan DELETE dan DETACH DELETE.

Memperbarui dan Menghapus Data Graf adalah pelajaran Neo4j Graph Database Fundamentals gratis di CoddyKit. Ini adalah pelajaran 3 dari 4. Kamu bisa membaca pelajaran lengkapnya di bawah secara gratis — lalu praktikkan langsung di browser dengan editor kode bawaan dan tutor AI 24/7. Ini adalah bagian dari jalur belajar Neo4j Graph Database Fundamentals, dan progresmu tersinkronisasi di web dan aplikasi CoddyKit. Kursus Neo4j Graph Database Fundamentals mencakup 4 pelajaran total.

Bagian dari pelajaran ini belum diterjemahkan dan ditampilkan dalam bahasa Inggris.

Modifying Your Graph Data

In this lesson, you'll learn how to update and delete existing nodes and relationships in your Neo4j graph using Cypher. Modifying data is crucial for keeping your graph accurate and up-to-date.

We'll cover the essential clauses: SET for changing properties, REMOVE for taking properties or labels away, and DELETE / DETACH DELETE for removing graph elements entirely.

Update Node Properties with SET

The SET clause is used to modify existing properties on nodes or relationships, or to add new ones. Let's start by updating a node's property.

This example first creates a 'Person' node, then updates their age.

CREATE (p:Person {name: 'Alice', age: 30})
RETURN p

MATCH (p:Person {name: 'Alice'})
SET p.age = 31
RETURN p.name, p.age

Update Relationship Properties

Just like nodes, relationships can also have properties. You can use SET to update these properties too. First, we create a relationship, then we update one of its properties.

CREATE (p1:Person {name: 'Bob'})-[:KNOWS {since: 2019}]->(p2:Person {name: 'Charlie'})
RETURN p1, p2

MATCH (p1:Person {name: 'Bob'})-[r:KNOWS]->(p2:Person {name: 'Charlie'})
SET r.since = 2020, r.status = 'Good Friends'
RETURN r.since, r.status

Add New Properties with SET

If you use SET with a property name that doesn't exist on a node or relationship, Cypher will simply add that new property. This is a handy way to extend your data model on the fly.

MATCH (p:Person {name: 'Alice'})
SET p.city = 'New York', p.occupation = 'Engineer'
RETURN p.name, p.city, p.occupation

Remove Properties with REMOVE

Sometimes you need to get rid of a property entirely. The REMOVE clause is designed for this. It can delete one or more properties from a node or a relationship.

Remember, REMOVE is for properties and labels, not for deleting entire nodes or relationships.

MATCH (p:Person {name: 'Alice'})
REMOVE p.occupation
RETURN p.name, p.age, p.city, p.occupation

Remove Node Labels

The REMOVE clause isn't just for properties; you can also use it to remove labels from a node. This can change the node's type or classification within your graph.

After removing the 'Person' label, the node still exists but is now just a generic node without that specific type.

MATCH (p:Person {name: 'Alice'})
REMOVE p:Person
RETURN p, labels(p)

Delete Relationships with DELETE

To remove a relationship, you use the DELETE clause. You must first MATCH the relationship you want to delete and then pass its variable to DELETE.

Note: DELETE can only remove relationships or nodes that have no relationships.

CREATE (a:User {id: 1})-[:LIKES]->(b:Product {id: 10})
RETURN a, b

MATCH (a:User {id: 1})-[r:LIKES]->(b:Product {id: 10})
DELETE r
RETURN a, b

Delete Nodes with DETACH DELETE

What if you want to delete a node that has relationships connected to it? A simple DELETE won't work and will give an error.

The solution is DETACH DELETE. This powerful clause deletes the node and all its incoming and outgoing relationships in one go.

CREATE (u:User {name: 'David'})-[:FOLLOWS]->(o:User {name: 'Eve'})
RETURN u, o

MATCH (u:User {name: 'David'})
DETACH DELETE u
RETURN u

Deletion Best Practices

Deleting data is permanent! Always exercise caution:

  • Test first: Run your MATCH clause with a RETURN to ensure you're selecting the correct elements before adding DELETE or DETACH DELETE.
  • Backup: For critical data, ensure you have backups.
  • Transaction awareness: In applications, deletions are often part of larger transactions.

Deletion Challenge

You have a (:Movie {title: 'Inception'}) node that is connected to many (:Actor) nodes via [:ACTED_IN] relationships. You want to remove the 'Inception' movie node and all its connections.

Lesson Summary

Great job! You've mastered the core Cypher clauses for modifying and deleting graph data:

  • SET: Updates existing properties or adds new ones to nodes and relationships.
  • REMOVE: Deletes specific properties or labels from nodes and relationships.
  • DELETE: Removes relationships or nodes that have no connections.
  • DETACH DELETE: The safest way to delete a node and all its associated relationships in one go.

Always be careful when deleting data, and verify your MATCH patterns first!

Pertanyaan yang Sering Diajukan

Apakah pelajaran “Memperbarui dan Menghapus Data Graf” gratis?

Ya — teks lengkap “Memperbarui dan Menghapus Data Graf” gratis dibaca di sini di web. Untuk praktiknya secara interaktif (editor kode bawaan dan tutor AI 24/7) dan buka sisa kursus Neo4j Graph Database Fundamentals, upgrade ke CoddyKit PRO. Kursus Neo4j Graph Database Fundamentals mencakup 4 pelajaran total.

Apa yang akan aku pelajari di “Memperbarui dan Menghapus Data Graf”?

Pelajari cara mengubah node dan relasi yang ada menggunakan SET dan REMOVE, serta menghapus data dengan aman menggunakan DELETE dan DETACH DELETE. Kamu berlatih Neo4j Graph Database Fundamentals dengan kode praktik yang langsung kamu jalankan di browser, dan tutor AI 24/7 menjawab pertanyaanmu saat kamu mengerjakan pelajaran ini.

Apakah aku perlu pengalaman untuk memulai Neo4j Graph Database Fundamentals?

Tidak diperlukan pengalaman sebelumnya. Neo4j Graph Database Fundamentals di CoddyKit dirancang untuk pemula hingga pelajar tingkat lanjut, jadi kamu bisa memulai di sini atau dari awal dan belajar sesuai kecepatan kamu sendiri. Ini adalah pelajaran 3 dari 4.

Berapa lama pelajaran “Memperbarui dan Menghapus Data Graf” memakan waktu?

Sebagian besar pelajaran CoddyKit memakan waktu sekitar 5–10 menit. Setiap pelajaran ringkas dan interaktif, jadi kamu membuat kemajuan stabil dan melanjutkan dari tempat kamu tinggalkan di web dan aplikasi.

Bisakah aku menulis dan menjalankan kode dalam pelajaran Neo4j Graph Database Fundamentals ini?

Ya. Setiap pelajaran Neo4j Graph Database Fundamentals menyertakan editor kode bawaan, jadi kamu menulis dan menjalankan kode nyata langsung di browser dan mendapatkan umpan balik AI instan — tidak diperlukan penyiapan lokal.

Semua pelajaran dalam kursus ini

  1. Memfilter dan Mengurutkan Hasil
  2. Agregasi dan Proyeksi
  3. Memperbarui dan Menghapus Data Graf
  4. Menggabungkan Kueri dengan WITH dan UNION
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