Getting a Single Node

Where we left off

Lesson 5 built the graph: 5 nodes, 6 directed edges, ready to query. The simplest possible query is "give me this one node back", which is what graph.get_node() does.

`graph.get_node()`

SELECT * FROM graph.get_node(
  graph_name := 'default',
  label := 'people',
  id := 'p1',
  hydrate := true
);

label is the node table's name as registered in Lesson 3 (people), id is the business ID from that table's id_column (p1, not an internal pggraph identifier). graph_name := 'default' refers to the graph you've been building all along, pggraph supports multiple named graphs in one database (Lesson 26), and every function that takes a graph_name defaults to 'default' if you never created another one.

`hydrate`: internal coordinates vs. real row data

The result includes a node_idx, pggraph's own internal array index for this node inside the CSR structure, useful for nothing on its own. The node column is what you actually want: the row's data as JSON, built from the columns you listed in graph.add_table(). That JSON is what hydrate := true produces, by reading the source table live. Every traversal, search, and path function in this course has the same hydrate option, and the same tradeoff: true costs an extra row lookup per result but gives you real data back; false (used in several later lessons) skips that lookup when you only need to know *that* something is connected, not its full contents.