fix(iris): return column descriptions

Closes #6912

agents/drivers/iris/src/main/java/com/dbx/agent/iris/IrisAgent.java

@@ -62,7 +62,7 @@ public final class IrisAgent extends ConfiguredJdbcAgent {
                             stringOrNull(rs, "COLUMN_DEFAULT"),
                             "YES".equalsIgnoreCase(stringOrNull(rs, "PRIMARY_KEY")),
                             null,
-                            null,
+                            stringOrNull(rs, "DESCRIPTION"),
                             intOrNull(rs, "NUMERIC_PRECISION"),
                             intOrNull(rs, "NUMERIC_SCALE"),
                             intOrNull(rs, "CHARACTER_MAXIMUM_LENGTH")
@@ -126,7 +126,7 @@ public final class IrisAgent extends ConfiguredJdbcAgent {
     private static String columnSql(String schema) {
         StringBuilder sql = new StringBuilder(
             "SELECT COLUMN_NAME, DATA_TYPE, IS_NULLABLE, COLUMN_DEFAULT, "
-                + "PRIMARY_KEY, NUMERIC_PRECISION, NUMERIC_SCALE, CHARACTER_MAXIMUM_LENGTH "
+                + "PRIMARY_KEY, DESCRIPTION, NUMERIC_PRECISION, NUMERIC_SCALE, CHARACTER_MAXIMUM_LENGTH "
                 + "FROM INFORMATION_SCHEMA.COLUMNS WHERE "
         );
         if (!isBlank(schema)) {

agents/drivers/iris/src/test/java/com/dbx/agent/iris/IrisAgentTest.java

@@ -19,6 +19,7 @@ import java.util.Map;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 class IrisAgentTest {
@@ -63,12 +64,45 @@ class IrisAgentTest {
         assertEquals("INTEGER", columns.get(0).getData_type());
         assertFalse(columns.get(0).getIs_nullable());
         assertTrue(columns.get(0).getIs_primary_key());
+        assertEquals("42", columns.get(0).getColumn_default());
+        assertEquals("identifier", columns.get(0).getComment());
+        assertEquals(Integer.valueOf(10), columns.get(0).getNumeric_precision());
+        assertEquals(Integer.valueOf(0), columns.get(0).getNumeric_scale());
+        assertNull(columns.get(0).getCharacter_maximum_length());
         assertEquals("NAME", columns.get(1).getName());
+        assertEquals("VARCHAR", columns.get(1).getData_type());
+        assertTrue(columns.get(1).getIs_nullable());
+        assertNull(columns.get(1).getColumn_default());
+        assertNull(columns.get(1).getComment());
+        assertNull(columns.get(1).getNumeric_precision());
+        assertNull(columns.get(1).getNumeric_scale());
         assertEquals(Integer.valueOf(64), columns.get(1).getCharacter_maximum_length());
         assertEquals(1, calls.size());
         assertFalse(calls.get(0).contains("LIMIT"));
         assertTrue(calls.get(0).contains("PRIMARY_KEY"));
+        assertTrue(calls.get(0).contains("DESCRIPTION"));
         assertTrue(calls.get(0).contains("INFORMATION_SCHEMA.COLUMNS"));
+        assertTrue(calls.get(0).contains("UPPER(TABLE_SCHEMA) = UPPER(?)"));
+    }
+
+    @Test
+    void readsDescriptionsWithoutSchemaFilter() {
+        List<String> calls = new ArrayList<>();
+        Connection conn = fakeConnection(
+            calls,
+            true,
+            Collections.emptyList(),
+            null,
+            Collections.emptyList()
+        );
+
+        List<ColumnInfo> columns = IrisAgent.irisColumns(conn, null, "People");
+
+        assertEquals("identifier", columns.get(0).getComment());
+        assertNull(columns.get(1).getComment());
+        assertEquals(1, calls.size());
+        assertTrue(calls.get(0).contains("DESCRIPTION"));
+        assertFalse(calls.get(0).contains("TABLE_SCHEMA"));
     }
 
     @Test
@@ -185,8 +219,11 @@ class IrisAgentTest {
                         "COLUMN_NAME", "ID",
                         "DATA_TYPE", "INTEGER",
                         "IS_NULLABLE", "NO",
+                        "COLUMN_DEFAULT", "42",
                         "PRIMARY_KEY", inlinePrimaryKey ? "YES" : "NO",
-                        "NUMERIC_PRECISION", 10
+                        "DESCRIPTION", "identifier",
+                        "NUMERIC_PRECISION", 10,
+                        "NUMERIC_SCALE", 0
                     ),
                     Map.of(
                         "COLUMN_NAME", "NAME",