feat: improve information_schema.columns

src/catalog/src/information_schema/columns.rs

@@ -51,6 +51,10 @@ const TABLE_NAME: &str = "table_name";
 const COLUMN_NAME: &str = "column_name";
 const DATA_TYPE: &str = "data_type";
 const SEMANTIC_TYPE: &str = "semantic_type";
+const COLUMN_DEFAULT: &str = "column_default";
+const IS_NULLABLE: &str = "is_nullable";
+const COLUMN_TYPE: &str = "column_type";
+const COLUMN_COMMENT: &str = "column_comment";
 
 impl InformationSchemaColumns {
     pub(super) fn new(catalog_name: String, catalog_manager: Weak<dyn CatalogManager>) -> Self {
@@ -69,6 +73,10 @@ impl InformationSchemaColumns {
             ColumnSchema::new(COLUMN_NAME, ConcreteDataType::string_datatype(), false),
             ColumnSchema::new(DATA_TYPE, ConcreteDataType::string_datatype(), false),
             ColumnSchema::new(SEMANTIC_TYPE, ConcreteDataType::string_datatype(), false),
+            ColumnSchema::new(COLUMN_DEFAULT, ConcreteDataType::string_datatype(), true),
+            ColumnSchema::new(IS_NULLABLE, ConcreteDataType::string_datatype(), false),
+            ColumnSchema::new(COLUMN_TYPE, ConcreteDataType::string_datatype(), false),
+            ColumnSchema::new(COLUMN_COMMENT, ConcreteDataType::string_datatype(), true),
         ]))
     }
 
@@ -126,6 +134,11 @@ struct InformationSchemaColumnsBuilder {
     column_names: StringVectorBuilder,
     data_types: StringVectorBuilder,
     semantic_types: StringVectorBuilder,
+
+    column_defaults: StringVectorBuilder,
+    is_nullables: StringVectorBuilder,
+    column_types: StringVectorBuilder,
+    column_comments: StringVectorBuilder,
 }
 
 impl InformationSchemaColumnsBuilder {
@@ -144,6 +157,10 @@ impl InformationSchemaColumnsBuilder {
             column_names: StringVectorBuilder::with_capacity(42),
             data_types: StringVectorBuilder::with_capacity(42),
             semantic_types: StringVectorBuilder::with_capacity(42),
+            column_defaults: StringVectorBuilder::with_capacity(42),
+            is_nullables: StringVectorBuilder::with_capacity(42),
+            column_types: StringVectorBuilder::with_capacity(42),
+            column_comments: StringVectorBuilder::with_capacity(42),
         }
     }
 
@@ -187,9 +204,8 @@ impl InformationSchemaColumnsBuilder {
                             &catalog_name,
                             &schema_name,
                             &table_name,
-                            &column.name,
-                            &column.data_type.name(),
                             semantic_type,
+                            column,
                         );
                     }
                 } else {
@@ -206,16 +222,31 @@ impl InformationSchemaColumnsBuilder {
         catalog_name: &str,
         schema_name: &str,
         table_name: &str,
-        column_name: &str,
-        data_type: &str,
         semantic_type: &str,
+        column_schema: &ColumnSchema,
     ) {
+        let data_type = &column_schema.data_type.name();
+
         self.catalog_names.push(Some(catalog_name));
         self.schema_names.push(Some(schema_name));
         self.table_names.push(Some(table_name));
-        self.column_names.push(Some(column_name));
+        self.column_names.push(Some(&column_schema.name));
         self.data_types.push(Some(data_type));
         self.semantic_types.push(Some(semantic_type));
+        self.column_defaults.push(
+            column_schema
+                .default_constraint()
+                .map(|s| format!("{}", s))
+                .as_deref(),
+        );
+        if column_schema.is_nullable() {
+            self.is_nullables.push(Some("Yes"));
+        } else {
+            self.is_nullables.push(Some("No"));
+        }
+        self.column_types.push(Some(data_type));
+        self.column_comments
+            .push(column_schema.column_comment().map(|x| x.as_ref()));
     }
 
     fn finish(&mut self) -> Result<RecordBatch> {
@@ -226,6 +257,10 @@ impl InformationSchemaColumnsBuilder {
             Arc::new(self.column_names.finish()),
             Arc::new(self.data_types.finish()),
             Arc::new(self.semantic_types.finish()),
+            Arc::new(self.column_defaults.finish()),
+            Arc::new(self.is_nullables.finish()),
+            Arc::new(self.column_types.finish()),
+            Arc::new(self.column_comments.finish()),
         ];
 
         RecordBatch::new(self.schema.clone(), columns).context(CreateRecordBatchSnafu)

src/catalog/src/information_schema/table_names.rs

@@ -25,3 +25,4 @@ pub const COLLATIONS: &str = "collations";
 pub const COLLATION_CHARACTER_SET_APPLICABILITY: &str = "collation_character_set_applicability";
 pub const CHECK_CONSTRAINTS: &str = "check_constraints";
 pub const EVENTS: &str = "events";
+pub const SCHEMATA: &str = "schemata";

src/datatypes/src/schema/column_schema.rs

@@ -109,6 +109,11 @@ impl ColumnSchema {
         &mut self.metadata
     }
 
+    /// Retrieve the column comment
+    pub fn column_comment(&self) -> Option<&String> {
+        self.metadata.get(COMMENT_KEY)
+    }
+
     pub fn with_time_index(mut self, is_time_index: bool) -> Self {
         self.is_time_index = is_time_index;
         if is_time_index {
@@ -315,12 +320,16 @@ mod tests {
 
     #[test]
     fn test_column_schema_with_metadata() {
-        let metadata = Metadata::from([("k1".to_string(), "v1".to_string())]);
+        let metadata = Metadata::from([
+            ("k1".to_string(), "v1".to_string()),
+            (COMMENT_KEY.to_string(), "test comment".to_string()),
+        ]);
         let column_schema = ColumnSchema::new("test", ConcreteDataType::int32_datatype(), true)
             .with_metadata(metadata)
             .with_default_constraint(Some(ColumnDefaultConstraint::null_value()))
             .unwrap();
         assert_eq!("v1", column_schema.metadata().get("k1").unwrap());
+        assert_eq!("test comment", column_schema.column_comment().unwrap());
         assert!(column_schema
             .metadata()
             .get(DEFAULT_CONSTRAINT_KEY)