Skip to main content Defining and validating database schemas with proper typing, index configuration, optional fields, unions, and migration strategies for schema changes
npx skills add waynesutton/convexskills --skill convex-schema-validator ai backend claude claude-skills convex database
Convex Schema Validator
Define and validate database schemas in Convex with proper typing, index configuration, optional fields, unions, and strategies for schema migrations.
Documentation Sources
Before implementing, do not assume; fetch the latest documentation:
Instructions
Basic Schema Definition
// convex/schema.ts
import { defineSchema, defineTable } from "convex/server";
import { v } from "convex/values";
export default defineSchema({
users: defineTable({
name: v.string(),
email: v.string(),
avatarUrl: v.optional(v.string()),
createdAt: v.number(),
}),
tasks: defineTable({
title: v.string(),
description: v.optional(v.string()),
completed: v.boolean(),
userId: v.id("users"),
priority: v.union(
v.literal("low"),
v.literal("medium"),
v.literal("high")
),
}),
});
Validator Types
Validator TypeScript Type Example v.string()string"hello"v.number()number42, 3.14v.boolean()booleantrue, falsev.null()nullnullv.int64()bigint9007199254740993nv.bytes()ArrayBufferBinary data v.id("table")Id<"table">Document reference v.array(v)T[][1, 2, 3]v.object({}){ ... }{ name: "..." }v.optional(v)T | undefinedOptional field v.union(...)T1 | T2Multiple types v.literal(x)"x"Exact value v.any()anyAny value v.record(k, v)Record<K, V>Dynamic keys
Index Configuration export default defineSchema({
messages: defineTable({
channelId: v.id("channels"),
authorId: v.id("users"),
content: v.string(),
sentAt: v.number(),
})
// Single field index
.index("by_channel", ["channelId"])
// Compound index
.index("by_channel_and_author", ["channelId", "authorId"])
// Index for sorting
.index("by_channel_and_time", ["channelId", "sentAt"]),
// Full-text search index
articles: defineTable({
title: v.string(),
body: v.string(),
category: v.string(),
})
.searchIndex("search_content", {
searchField: "body",
filterFields: ["category"],
}),
});
Complex Types export default defineSchema({
// Nested objects
profiles: defineTable({
userId: v.id("users"),
settings: v.object({
theme: v.union(v.literal("light"), v.literal("dark")),
notifications: v.object({
email: v.boolean(),
push: v.boolean(),
}),
}),
}),
// Arrays of objects
orders: defineTable({
customerId: v.id("users"),
items: v.array(v.object({
productId: v.id("products"),
quantity: v.number(),
price: v.number(),
})),
status: v.union(
v.literal("pending"),
v.literal("processing"),
v.literal("shipped"),
v.literal("delivered")
),
}),
// Record type for dynamic keys
analytics: defineTable({
date: v.string(),
metrics: v.record(v.string(), v.number()),
}),
});
Discriminated Unions export default defineSchema({
events: defineTable(
v.union(
v.object({
type: v.literal("user_signup"),
userId: v.id("users"),
email: v.string(),
}),
v.object({
type: v.literal("purchase"),
userId: v.id("users"),
orderId: v.id("orders"),
amount: v.number(),
}),
v.object({
type: v.literal("page_view"),
sessionId: v.string(),
path: v.string(),
})
)
).index("by_type", ["type"]),
});
Optional vs Nullable Fields export default defineSchema({
items: defineTable({
// Optional: field may not exist
description: v.optional(v.string()),
// Nullable: field exists but can be null
deletedAt: v.union(v.number(), v.null()),
// Optional and nullable
notes: v.optional(v.union(v.string(), v.null())),
}),
});
Index Naming Convention Always include all indexed fields in the index name:
export default defineSchema({
posts: defineTable({
authorId: v.id("users"),
categoryId: v.id("categories"),
publishedAt: v.number(),
status: v.string(),
})
// Good: descriptive names
.index("by_author", ["authorId"])
.index("by_author_and_category", ["authorId", "categoryId"])
.index("by_category_and_status", ["categoryId", "status"])
.index("by_status_and_published", ["status", "publishedAt"]),
});
Schema Migration Strategies
Adding New Fields // Before
users: defineTable({
name: v.string(),
email: v.string(),
})
// After - add as optional first
users: defineTable({
name: v.string(),
email: v.string(),
avatarUrl: v.optional(v.string()), // New optional field
})
Backfilling Data // convex/migrations.ts
import { internalMutation } from "./_generated/server";
import { v } from "convex/values";
export const backfillAvatars = internalMutation({
args: {},
returns: v.number(),
handler: async (ctx) => {
const users = await ctx.db
.query("users")
.filter((q) => q.eq(q.field("avatarUrl"), undefined))
.take(100);
for (const user of users) {
await ctx.db.patch(user._id, {
avatarUrl: `https://api.dicebear.com/7.x/initials/svg?seed=${user.name}`,
});
}
return users.length;
},
});
Making Optional Fields Required // Step 1: Backfill all null values
// Step 2: Update schema to required
users: defineTable({
name: v.string(),
email: v.string(),
avatarUrl: v.string(), // Now required after backfill
})
Examples
Complete E-commerce Schema // convex/schema.ts
import { defineSchema, defineTable } from "convex/server";
import { v } from "convex/values";
export default defineSchema({
users: defineTable({
email: v.string(),
name: v.string(),
role: v.union(v.literal("customer"), v.literal("admin")),
createdAt: v.number(),
})
.index("by_email", ["email"])
.index("by_role", ["role"]),
products: defineTable({
name: v.string(),
description: v.string(),
price: v.number(),
category: v.string(),
inventory: v.number(),
isActive: v.boolean(),
})
.index("by_category", ["category"])
.index("by_active_and_category", ["isActive", "category"])
.searchIndex("search_products", {
searchField: "name",
filterFields: ["category", "isActive"],
}),
orders: defineTable({
userId: v.id("users"),
items: v.array(v.object({
productId: v.id("products"),
quantity: v.number(),
priceAtPurchase: v.number(),
})),
total: v.number(),
status: v.union(
v.literal("pending"),
v.literal("paid"),
v.literal("shipped"),
v.literal("delivered"),
v.literal("cancelled")
),
shippingAddress: v.object({
street: v.string(),
city: v.string(),
state: v.string(),
zip: v.string(),
country: v.string(),
}),
createdAt: v.number(),
updatedAt: v.number(),
})
.index("by_user", ["userId"])
.index("by_user_and_status", ["userId", "status"])
.index("by_status", ["status"]),
reviews: defineTable({
productId: v.id("products"),
userId: v.id("users"),
rating: v.number(),
comment: v.optional(v.string()),
createdAt: v.number(),
})
.index("by_product", ["productId"])
.index("by_user", ["userId"]),
});
Using Schema Types in Functions // convex/products.ts
import { query, mutation } from "./_generated/server";
import { v } from "convex/values";
import { Doc, Id } from "./_generated/dataModel";
// Use Doc type for full documents
type Product = Doc<"products">;
// Use Id type for references
type ProductId = Id<"products">;
export const get = query({
args: { productId: v.id("products") },
returns: v.union(
v.object({
_id: v.id("products"),
_creationTime: v.number(),
name: v.string(),
description: v.string(),
price: v.number(),
category: v.string(),
inventory: v.number(),
isActive: v.boolean(),
}),
v.null()
),
handler: async (ctx, args): Promise<Product | null> => {
return await ctx.db.get(args.productId);
},
});
Best Practices
Never run npx convex deploy unless explicitly instructed
Never run any git commands unless explicitly instructed
Always define explicit schemas rather than relying on inference
Use descriptive index names that include all indexed fields
Start with optional fields when adding new columns
Use discriminated unions for polymorphic data
Validate data at the schema level, not just in functions
Plan index strategy based on query patterns
Common Pitfalls
Missing indexes for queries - Every withIndex needs a corresponding schema index
Wrong index field order - Fields must be queried in order defined
Using v.any() excessively - Lose type safety benefits
Not making new fields optional - Breaks existing data
Forgetting system fields - _id and _creationTime are automatic
References Create or update AgentSkills. Use when designing, structuring, or packaging skills with scripts, references, and assets.
Create or update AgentSkills. Use when designing, structuring, or packaging skills with scripts, references, and assets.
Set up and use 1Password CLI (op). Use when installing the CLI, enabling desktop app integration, signing in (single or multi-account), or reading/injecting/running secrets via op.
CLI to manage emails via IMAP/SMTP. Use `himalaya` to list, read, write, reply, forward, search, and organize emails from the terminal. Supports multiple accounts and message composition with MML (MIME Meta Language).
Create or update AgentSkills. Use when designing, structuring, or packaging skills with scripts, references, and assets.
Create or update AgentSkills. Use when designing, structuring, or packaging skills with scripts, references, and assets.
Set up and use 1Password CLI (op). Use when installing the CLI, enabling desktop app integration, signing in (single or multi-account), or reading/injecting/running secrets via op.
CLI to manage emails via IMAP/SMTP. Use `himalaya` to list, read, write, reply, forward, search, and organize emails from the terminal. Supports multiple accounts and message composition with MML (MIME Meta Language).