no more negative prices

Author: jerrinot

kafka-questdb-connector-samples/stocks/readme.md

@@ -1,3 +1,5 @@
+
+
 Postgres -> Kafka:
 ```shell
 curl -X POST -H "Content-Type: application/json" -d  '{"name":"debezium_source","config":{"tasks.max":1,"database.hostname":"postgres","database.port":5432,"database.user":"postgres","database.password":"postgres","connector.class":"io.debezium.connector.postgresql.PostgresConnector","database.dbname":"postgres","database.server.name":"dbserver1"}} ' localhost:8083/connectors

kafka-questdb-connector-samples/stocks/src/main/java/io/questdb/kafka/samples/StockRepository.java

@@ -18,7 +18,7 @@
 public interface StockRepository extends CrudRepository<Stock, String> {
 
     @Modifying
-    @Query("UPDATE stock SET price = price + :delta, last_update = :timestamp WHERE symbol = :symbol")
+    @Query("UPDATE stock SET price = GREATEST(0, price + :delta), last_update = :timestamp WHERE symbol = :symbol")
     boolean updateBySymbol(@Param("symbol") String symbol, @Param("delta") double delta, @Param("timestamp") Timestamp timestamp);
 
     @Query("SELECT symbol FROM stock")