From 922258431c9fffc50b74b18461abb3c219a7d2ab Mon Sep 17 00:00:00 2001
From: Vojta Biberle <vojtech.biberle@gmail.com>
Date: Thu, 23 Jan 2025 12:51:43 +0100
Subject: [PATCH] DMD-33 add test for empty schema

---
 .../Snowflake/SnowflakeSchemaReflection.php   | 76 ++++++++++++++++++-
 .../Schema/SnowflakeSchemaReflectionTest.php  |  8 ++
 2 files changed, 80 insertions(+), 4 deletions(-)

diff --git a/packages/php-table-backend-utils/src/Schema/Snowflake/SnowflakeSchemaReflection.php b/packages/php-table-backend-utils/src/Schema/Snowflake/SnowflakeSchemaReflection.php
index 18df427d0..a7efd0a8f 100644
--- a/packages/php-table-backend-utils/src/Schema/Snowflake/SnowflakeSchemaReflection.php
+++ b/packages/php-table-backend-utils/src/Schema/Snowflake/SnowflakeSchemaReflection.php
@@ -5,6 +5,7 @@
 namespace Keboola\TableBackendUtils\Schema\Snowflake;
 
 use Doctrine\DBAL\Connection;
+use Keboola\Datatype\Definition\Snowflake;
 use Keboola\TableBackendUtils\Column\ColumnCollection;
 use Keboola\TableBackendUtils\Column\Snowflake\SnowflakeColumn;
 use Keboola\TableBackendUtils\Escaping\Snowflake\SnowflakeQuote;
@@ -68,18 +69,33 @@ 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, '16777216') || ')'
+        
+        -- 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, '') || ')'
+        
+        -- Map binary and varbinary - Snowflake don't have length for binary in INFORMATION_SCHEMA - handled in code
+        WHEN DATA_TYPE IN ('BINARY', 'VARBINARY') THEN
+            'BINARY' 
+ 
+        -- 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 +112,12 @@ 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{
@@ -146,6 +168,18 @@ public function getDefinitions(): array
             // array{TABLE_NAME: string, name: string, type: string, default: string, null?: string}.
             // @phpstan-ignore-next-line
             $column['null?'] = ($column['null?'] === 'YES' ? 'Y' : 'N');
+
+            // Snowflake have length for binary columns only in DESC TABLE or SHOW COLUMNS
+            if ($column['type'] === Snowflake::TYPE_BINARY) {
+                $info = $this->getBinaryColumnLength($column['TABLE_NAME'], $column['name']);
+                if ($info !== null) {
+                    $column['type'] = sprintf(
+                        '%s(%s)',
+                        Snowflake::TYPE_BINARY,
+                        $info['length'],
+                    );
+                }
+            }
             $tables[$column['TABLE_NAME']]['COLUMNS'][] = SnowflakeColumn::createFromDB($column);
         }
 
@@ -166,4 +200,38 @@ public function getDefinitions(): array
         }
         return $definitions;
     }
+
+    /**
+     * @return array{type: string, length: string}|null
+     */
+    private function getBinaryColumnLength(string $tableName, string $columnName): ?array
+    {
+        $sql = sprintf('DESCRIBE TABLE %s', SnowflakeQuote::quote($tableName));
+        /** @var array<
+         *     int,
+         *      array{
+         *          name: string,
+         *          type: string,
+         *          kind: string,
+         *          null?: string,
+         *          default: ?string,
+         *          "primary key": string,
+         *          "unique key": string,
+         *          check: ?string,
+         *          expression: ?string,
+         *          comment: ?string,
+         *          "policy name": ?string,
+         *          "privacy domain": ?string
+         *      }
+         * > $columns
+         */
+        $columns = $this->connection->fetchAllAssociative($sql);
+        foreach ($columns as $column) {
+            if ($column['name'] === $columnName) {
+                return SnowflakeColumn::extractTypeAndLengthFromDB($column['type']);
+            }
+        }
+
+        return null;
+    }
 }
diff --git a/packages/php-table-backend-utils/tests/Functional/Snowflake/Schema/SnowflakeSchemaReflectionTest.php b/packages/php-table-backend-utils/tests/Functional/Snowflake/Schema/SnowflakeSchemaReflectionTest.php
index da5a78232..d45855e3e 100644
--- a/packages/php-table-backend-utils/tests/Functional/Snowflake/Schema/SnowflakeSchemaReflectionTest.php
+++ b/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);
+    }
 }