Add unique constraint to LlmModelCost on model, provider, unit

Introduces a unique index on the combination of llmModelId, credentialProvider, and unit in the LlmModelCost table to prevent duplicate cost entries. Updates the seed migration to handle conflicts on this unique key by doing nothing on conflict.

autogpt_platform/backend/migrations/20251126113000_add_llm_registry/migration.sql

@@ -70,6 +70,9 @@ CREATE INDEX "LlmModelCost_llmModelId_idx" ON "LlmModelCost"("llmModelId");
 -- CreateIndex
 CREATE INDEX "LlmModelCost_credentialProvider_idx" ON "LlmModelCost"("credentialProvider");
 
+-- CreateIndex
+CREATE UNIQUE INDEX "LlmModelCost_llmModelId_credentialProvider_unit_key" ON "LlmModelCost"("llmModelId", "credentialProvider", "unit");
+
 -- AddForeignKey
 ALTER TABLE "LlmModel" ADD CONSTRAINT "LlmModel_providerId_fkey" FOREIGN KEY ("providerId") REFERENCES "LlmProvider"("id") ON DELETE RESTRICT ON UPDATE CASCADE;
 

autogpt_platform/backend/migrations/20251126120000_seed_llm_registry/migration.sql

@@ -221,5 +221,6 @@ FROM (VALUES
     ('v0-1.0-md', 1)
 ) AS costs(model_slug, cost)
 JOIN model_ids m ON m."slug" = costs.model_slug
-JOIN provider_ids p ON p."id" = m."providerId";
+JOIN provider_ids p ON p."id" = m."providerId"
+ON CONFLICT ("llmModelId", "credentialProvider", "unit") DO NOTHING;
 

autogpt_platform/backend/schema.prisma

@@ -1198,6 +1198,7 @@ model LlmModelCost {
   llmModelId String
   Model      LlmModel @relation(fields: [llmModelId], references: [id], onDelete: Cascade)
 
+  @@unique([llmModelId, credentialProvider, unit])
   @@index([llmModelId])
   @@index([credentialProvider])
 }