Add non-nullable info to schema output. (#2117)

docs/source/release.rst

@@ -10,6 +10,7 @@ Release Notes
 * :feature:`2126` Add translation rules for isnull() and notnull() for pyspark backend
 * :feature:`2062` Implement read_csv for omniscidb backend
 * :feature:`2060` Add initial support for ibis.random function
+* :feature:`2117` Add non-nullable info to schema output
 * :support:`2096` Added round() support for OmniSciDB
 * :feature:`2125` [OmniSciDB] Add support for within, d_fully_within and point
 * :support:`2113` Enabled cumulative ops support for OmniSciDB

ibis/expr/datatypes.py

@@ -83,7 +83,9 @@ def __repr__(self) -> str:
         )
 
     def __str__(self) -> str:
-        return self.name.lower()
+        return '{}{}'.format(
+            self.name.lower(), '[non-nullable]' if not self.nullable else ''
+        )
 
     @property
     def name(self) -> str:

ibis/expr/tests/test_schema.py

@@ -149,3 +149,20 @@ def test_empty_schema():
 ibis.Schema {
 }"""
     assert result == expected
+
+
+def test_nullable_output():
+    sch = ibis.schema(
+        [
+            ('foo', 'int64'),
+            ('bar', ibis.expr.datatypes.int64(nullable=False)),
+            ('baz', 'boolean*'),
+        ]
+    )
+
+    sch_str = str(sch)
+    assert 'foo  int64' in sch_str
+    assert 'foo  int64[non-nullable]' not in sch_str
+    assert 'bar  int64[non-nullable]' in sch_str
+    assert 'baz  boolean' in sch_str
+    assert 'baz  boolean[non-nullable]' not in sch_str