Bring json and vector functions from sqrl project

[velo]

No description provided.

[Copilot]

Pull Request Overview

This pull request brings a set of JSON functions and corresponding utilities from the sqrl project into the codebase, as well as introduces a PostgreSQL vector type serializer.

• Introduces new JSON functions and aggregators (e.g., ObjectAgg, JsonToString, JsonQuery, JsonObject, JsonExtract, JsonArrayAgg, and JsonArray).
• Implements a new PostgreSQL vector type serializer and extends JDBC testing to verify the updated functionality.

Reviewed Changes

Copilot reviewed 29 out of 34 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
types/json-type/src/main/java/com/datasqrl/types/json/functions/ObjectAgg.java	New aggregation class for JSON objects.
types/json-type/src/main/java/com/datasqrl/types/json/functions/JsonToString.java	New function converting JSON to string (note the included FIXME comment).
types/json-type/src/main/java/com/datasqrl/types/json/functions/JsonQuery.java	New JSON query function using JsonPath.
types/json-type/src/main/java/com/datasqrl/types/json/functions/JsonObjectAgg.java	Aggregation of JSON objects into one.
types/json-type/src/main/java/com/datasqrl/types/json/functions/JsonObject.java	Function to create JSON objects from key-value pairs.
types/json-type/src/main/java/com/datasqrl/types/json/functions/JsonFunctions.java	Static holder class for JSON functions.
types/json-type/src/main/java/com/datasqrl/types/json/functions/JsonExtract.java	Provides different overloads to extract JSON values with default returns.
types/json-type/src/main/java/com/datasqrl/types/json/functions/JsonExists.java	Checks if a given JSON path exists in a JSON object.
types/json-type/src/main/java/com/datasqrl/types/json/functions/JsonConcat.java	Merges two JSON objects into one.
types/json-type/src/main/java/com/datasqrl/types/json/functions/JsonArrayAgg.java	Aggregates JSON elements into an array.
types/json-type/src/main/java/com/datasqrl/types/json/functions/JsonArray.java	Creates a JSON array from arbitrary objects, including JSON types.
types/json-type/src/main/java/com/datasqrl/types/json/functions/ArrayAgg.java	Implements a helper class for aggregation operations.
connectors/postgresql-connector/src/test/java/com/datasqrl/connector/postgresql/jdbc/FlinkJdbcTest.java	Tests to verify JSON and vector function integration with PostgreSQL via JDBC.
connectors/postgresql-connector/src/main/java/com/datasqrl/connector/postgresql/type/PostgresVectorTypeSerializer.java	New serializer implementation for handling vector types with PostgreSQL.

Files not reviewed (5)

• connectors/postgresql-connector/pom.xml: Language not supported
• connectors/postgresql-connector/src/main/resources/META-INF/services/com.datasqrl.connector.postgresql.type.JdbcTypeSerializer: Language not supported
• pom.xml: Language not supported
• testing/system-functions-sample/pom.xml: Language not supported
• types/json-type/pom.xml: Language not supported

Comments suppressed due to low confidence (2)

types/json-type/src/main/java/com/datasqrl/types/json/functions/JsonToString.java:25

• The FIXME comment indicates unresolved behavior regarding the sqrl cast. Consider addressing the cast functionality by either implementing the missing interface or clarifying the intended behavior.

public class JsonToString extends ScalarFunction implements /* FIXME what to do about the sqrl cast? SqrlCastFunction, */ AutoRegisterSystemFunction {

types/json-type/src/main/java/com/datasqrl/types/json/functions/JsonObject.java:59

• [nitpick] There is an inconsistency in accessing the JSON content; elsewhere the getter method (getJson()) is used. For better consistency and maintainability, consider using the accessor method uniformly.

objectNode.put(key, type.json);