Get By Predicate

The GetPred request retrieves entries from a store that match a specified predicate condition on their metadata.

• Input: Store name and predicate condition.

• Behavior: Returns all entries whose metadata matches the predicate condition.

• Response: A list of matching entries.

Click to expand source code

import { createDbClient } from "ahnlich-client-node";
import { GetPred } from "ahnlich-client-node/grpc/db/query_pb";
import { PredicateCondition, Predicate, Equals } from "ahnlich-client-node/grpc/predicate_pb";
import { MetadataValue } from "ahnlich-client-node/grpc/metadata_pb";

async function getByPredicate() {
  const client = createDbClient("127.0.0.1:1369");

  const response = await client.getPred(
    new GetPred({
      store: "my_store",
      condition: new PredicateCondition({
        kind: {
          case: "value",
          value: new Predicate({
            kind: {
              case: "equals",
              value: new Equals({
                key: "label",
                value: new MetadataValue({ value: { case: "rawString", value: "A" } }),
              }),
            },
          }),
        },
      }),
    })
  );

  console.log(`Found ${response.entries.length} entries with label='A'`);
}

getByPredicate();

Parameters

Parameter	Type	Required	Description
store	string	Yes	The name of the store
condition	PredicateCondition	Yes	The filter condition

Available Predicates

Predicate	Description
Equals	Match exact value
NotEquals	Exclude exact value
In	Match if value is in a given set
NotIn	Match if value is not in a given set
Contains	Match if string contains substring
NotContains	Match if string does not contain substring

Example with NotEquals

Click to expand source code

import { createDbClient } from "ahnlich-client-node";
import { GetPred } from "ahnlich-client-node/grpc/db/query_pb";
import { PredicateCondition, Predicate, NotEquals } from "ahnlich-client-node/grpc/predicate_pb";
import { MetadataValue } from "ahnlich-client-node/grpc/metadata_pb";

async function getNotEqualsPredicate() {
  const client = createDbClient("127.0.0.1:1369");

  const response = await client.getPred(
    new GetPred({
      store: "my_store",
      condition: new PredicateCondition({
        kind: {
          case: "value",
          value: new Predicate({
            kind: {
              case: "notEquals",
              value: new NotEquals({
                key: "status",
                value: new MetadataValue({ value: { case: "rawString", value: "archived" } }),
              }),
            },
          }),
        },
      }),
    })
  );

  console.log(`Found ${response.entries.length} non-archived entries`);
}

getNotEqualsPredicate();

Example with AND Condition

Click to expand source code

import { createDbClient } from "ahnlich-client-node";
import { GetPred } from "ahnlich-client-node/grpc/db/query_pb";
import { 
  PredicateCondition, 
  Predicate, 
  Equals, 
  AndCondition 
} from "ahnlich-client-node/grpc/predicate_pb";
import { MetadataValue } from "ahnlich-client-node/grpc/metadata_pb";

async function getWithAndCondition() {
  const client = createDbClient("127.0.0.1:1369");

  const response = await client.getPred(
    new GetPred({
      store: "my_store",
      condition: new PredicateCondition({
        kind: {
          case: "and",
          value: new AndCondition({
            left: new PredicateCondition({
              kind: {
                case: "value",
                value: new Predicate({
                  kind: {
                    case: "equals",
                    value: new Equals({
                      key: "category",
                      value: new MetadataValue({ value: { case: "rawString", value: "electronics" } }),
                    }),
                  },
                }),
              },
            }),
            right: new PredicateCondition({
              kind: {
                case: "value",
                value: new Predicate({
                  kind: {
                    case: "equals",
                    value: new Equals({
                      key: "brand",
                      value: new MetadataValue({ value: { case: "rawString", value: "Apple" } }),
                    }),
                  },
                }),
              },
            }),
          }),
        },
      }),
    })
  );

  console.log(`Found ${response.entries.length} Apple electronics`);
}

getWithAndCondition();

Notes

• For optimal performance, create predicate indices on frequently filtered fields
• Complex conditions (AND/OR) are supported for advanced filtering
• See Type Meanings for more details on predicates