DMD-33 add test for empty schema

packages/php-table-backend-utils/src/Schema/Snowflake/SnowflakeSchemaReflection.php

@@ -68,18 +68,29 @@ public function getDefinitions(): array
             SnowflakeQuote::quote($this->schemaName),
         );
 
+        // Snowflake maps in DESC TABLE few data-type aliases to their basic types
+        // but in INFORMATION_SCHEMA.COLUMNS table keep data-type aliases
+        // here is implemented same mapping as DESC TABLE uses
         $columnsQuery = sprintf(
             <<<SQL
 SELECT 
     TABLE_NAME,
     COLUMN_NAME AS "name",
     CASE 
+        -- Map string types to VARCHAR
         WHEN DATA_TYPE IN ('CHAR', 'VARCHAR', 'STRING', 'TEXT') THEN 
-            DATA_TYPE || '(' || CHARACTER_MAXIMUM_LENGTH || ')'
+            'VARCHAR(' || COALESCE(CHARACTER_MAXIMUM_LENGTH::STRING, 'MAX') || ')'
+        
+        -- Map numeric types to NUMBER
         WHEN DATA_TYPE IN ('NUMBER', 'DECIMAL', 'NUMERIC') THEN 
-            DATA_TYPE || '(' || COALESCE(NUMERIC_PRECISION::STRING, '') || ',' || COALESCE(NUMERIC_SCALE::STRING, '0') || ')'
-        ELSE 
-            DATA_TYPE
+            'NUMBER(' || COALESCE(NUMERIC_PRECISION::STRING, '') || ',' || COALESCE(NUMERIC_SCALE::STRING, '0') || ')'
+        
+        -- Map date and time types to their respective names - DATE is mapped directly to DATE
+        WHEN DATA_TYPE IN ('DATETIME', 'TIME', 'TIMESTAMP', 'TIMESTAMP_LTZ', 'TIMESTAMP_TZ', 'TIMESTAMP_NTZ') THEN 
+            DATA_TYPE || '(' || COALESCE(DATETIME_PRECISION::STRING, '') || ')'
+ 
+        -- Default case for all other types as they are mapped by DESC TABLE direcly to themself
+        ELSE DATA_TYPE
     END AS "type",
     COLUMN_DEFAULT AS "default",
     IS_NULLABLE AS "null?"
@@ -96,6 +107,12 @@ public function getDefinitions(): array
 
         /** @var array<int, array{TABLE_NAME: string, TABLE_TYPE: string, BYTES: int, ROW_COUNT: int}> $informations */
         $informations = $this->connection->fetchAllAssociative($informationsQuery);
+
+        // short-circuit > no tables no need to continue
+        if (count($informations) === 0) {
+            return [];
+        }
+
         /** @var array<int, array{TABLE_NAME: string, name: string, type: string, default: string, null?: string}> $columns */
         $columns = $this->connection->fetchAllAssociative($columnsQuery);
         /** @var array<int, array{

packages/php-table-backend-utils/tests/Functional/Snowflake/Schema/SnowflakeSchemaReflectionTest.php

@@ -155,4 +155,12 @@ public function testGetDefinitions(): void
         self::assertFalse($definitions[$genericViewKey]->isTemporary());
         self::assertEquals('view', $definitions[$genericViewKey]->getTableType()->value);
     }
+
+    public function testGetDefinitionsWithEmptySchema(): void
+    {
+        $this->createSchema(self::TEST_SCHEMA);
+        $definitions = $this->schemaRef->getDefinitions();
+
+        self::assertCount(0, $definitions);
+    }
 }