如何在Firebase中存储Facebook群组投票应用的两个数据表及导入CSV？

Hey there! Since you're used to SQL's table-and-row structure, Firebase Firestore's NoSQL document model might feel a bit unfamiliar at first—but let's map your existing tables directly to a Firebase structure that fits your voting app's needs perfectly.

1. Mapping the Users Table to Firebase #

Your original Users table stores group members with Userid, Status, and Date. In Firestore, we'll use a collection for users, with each user as a document (using their Userid as the document ID for fast lookups—critical for your login/validation flow):

• Collection name: users
• Document ID: Use the Facebook Userid (e.g., 123456789) as the unique document key (this replaces SQL's primary key)
• Document fields:
  • status: String (e.g., "active_member" to confirm they're part of the group)
  • joinDate: Timestamp (stores the date they joined the group, replacing your original Date column)
  • hasVoted: Boolean (add this field to quickly check if the user has already voted—way more efficient than cross-referencing a separate table later)

Importing Your Users CSV #

Since you have a CSV of group members, you can import it directly into Firestore:

• Go to the Firebase Console → Firestore Database → Import/Export
• Upload your CSV, and map the CSV columns to the fields above. Make sure to set the Userid column as the Document ID during import.
• Alternatively, use the Firebase CLI command: firebase firestore:import users.csv --collection=users (just ensure your CSV has a Userid column to use as the document key)

2. Mapping the Votes Table to Firebase #

Your Votes table tracks candidate votes with Cid, Cname, and NoofVotes. We'll use another collection for candidates, where each document represents a candidate and their vote count:

• Collection name: candidates
• Document ID: Use the candidate's Cid (e.g., candidate_01) as the document ID
• Document fields:
  • name: String (replaces Cname—the candidate's name)
  • voteCount: Number (replaces NoofVotes—starts at 0, increments when someone votes)

Key Logic for Your Voting Flow (Tied to This Structure) #

Since your app needs to verify users are group members and haven't voted yet:

1. After Facebook login, fetch the user's Userid
2. Query the users collection for the document with that Userid:
   • If the document doesn't exist → user isn't a group member, block access
   • If hasVoted is true → user already voted, block access
3. When the user votes, use a Firebase Transaction to safely update both the candidate's vote count and the user's hasVoted status (prevents duplicate votes or race conditions):

   // Example transaction logic (JavaScript)
   const voteTransaction = async (userId, candidateId) => {
     const db = firebase.firestore();
     await db.runTransaction(async (transaction) => {
       // Get user document
       const userDoc = db.collection('users').doc(userId);
       const userSnapshot = await transaction.get(userDoc);
       if (!userSnapshot.exists || userSnapshot.data().hasVoted) {
         throw new Error('User cannot vote');
       }
       // Get candidate document
       const candidateDoc = db.collection('candidates').doc(candidateId);
       const candidateSnapshot = await transaction.get(candidateDoc);
       if (!candidateSnapshot.exists) {
         throw new Error('Candidate does not exist');
       }
       // Update vote count and user status
       transaction.update(candidateDoc, {
         voteCount: candidateSnapshot.data().voteCount + 1
       });
       transaction.update(userDoc, { hasVoted: true });
     });
   };
   

Quick SQL vs. Firestore Comparison #

This structure is optimized for your app's read-heavy flow (checking user eligibility) and ensures safe, atomic updates when voting.

内容的提问来源于stack exchange，提问作者Arshak Anjum