Merge pull request #21715 from WilliamDAssafMSFT/20220413-with-check-check

20220413 1812 refresh articles, account for trusted FK

Author: tamarakhader

docs/relational-databases/tables/disable-foreign-key-constraints-with-insert-and-update-statements.md

@@ -2,7 +2,7 @@
 description: "Disable Foreign Key Constraints with INSERT and UPDATE Statements"
 title: Disable Foreign Key Constraints in INSERT and UPDATE Statements
 ms.custom: "seo-lt-2019"
-ms.date: "10/21/2021"
+ms.date: "04/13/2022"
 ms.prod: sql
 ms.prod_service: "database-engine, sql-database, synapse-analytics, pdw"
 ms.reviewer: ""
@@ -18,7 +18,7 @@ author: WilliamDAssafMSFT
 ms.author: wiassaf
 monikerRange: ">=aps-pdw-2016||=azuresqldb-current||=azure-sqldw-latest||>=sql-server-2016||>=sql-server-linux-2017||=azuresqldb-mi-current"
 ---
-# Disable Foreign Key Constraints with INSERT and UPDATE Statements
+# Disable foreign key constraints with INSERT and UPDATE statements
 [!INCLUDE [sqlserver2016-asdb-asdbmi-asa-pdw](../../includes/applies-to-version/sqlserver2016-asdb-asdbmi-asa-pdw.md)]
 
   You can disable a foreign key constraint during INSERT and UPDATE transactions in [!INCLUDE[ssnoversion](../../includes/ssnoversion-md.md)] by using [!INCLUDE[ssManStudioFull](../../includes/ssmanstudiofull-md.md)] or [!INCLUDE[tsql](../../includes/tsql-md.md)]. Use this option if you know that new data will not violate the existing constraint or if the constraint applies only to the data already in the database.  
@@ -29,7 +29,7 @@ monikerRange: ">=aps-pdw-2016||=azuresqldb-current||=azure-sqldw-latest||>=sql-s
 ##  <a name="Security"></a><a name="Permissions"></a> Permissions  
  Requires ALTER permission on the table.  
 
-##  <a name="SSMSProcedure"></a> Use SQL Server Management Studio  
+##  <a name="SSMSProcedure"></a> Use SQL Server Management Studio
 
 #### To disable a foreign key constraint for INSERT and UPDATE statements  
 
@@ -42,6 +42,11 @@ monikerRange: ">=aps-pdw-2016||=azuresqldb-current||=azure-sqldw-latest||>=sql-s
 4.  Select **Close**.  
 
 5.  To re-enable the constraint when desired, reverse the above steps. Select **Enforce Foreign Key Constraint** and select **Yes** from the drop-down menu.  
+
+6.  To trust the constraint by checking the existing data in the foreign key's relationship, select **Check Existing Data on Creation Or Re-Enabling** and select **Yes** from the drop-down menu. This would ensure the foreign key constraint is trusted. 
+
+-   If **Check Existing Data on Creation Or Re-Enabling** is set to **No**, the foreign key does not check existing data when it is re-enabled. The query optimizer is therefore unable to consider potential performance improvements. Trusted foreign keys are recommended because they can be used to simplify execution plans with assumptions based on the foreign key constraint. To check whether foreign keys are trusted in your database, see a sample query later in this article.
+
 
 ##  <a name="TsqlProcedure"></a> Use Transact-SQL  
 
@@ -70,8 +75,27 @@ monikerRange: ">=aps-pdw-2016||=azuresqldb-current||=azure-sqldw-latest||>=sql-s
     CHECK CONSTRAINT FK_PurchaseOrderHeader_Employee_EmployeeID;  
     GO  
     ``` 
+
+5. Verify that the constraint in your environment is both trusted and enabled. If `is_not_trusted` = 1, then the foreign key does not check existing data when it is re-enabled or re-created. The query optimizer is therefore unable to consider potential performance improvements. Trusted foreign keys are recommended because they can be used to simplify execution plans with assumptions based on the foreign key constraint. Copy and paste the following example into the query window and select **Execute**.
+
+    ```sql
+    SELECT o.name, fk.name, fk.is_not_trusted, fk.is_disabled
+    FROM sys.foreign_keys AS fk
+    INNER JOIN sys.objects AS o ON fk.parent_object_id = o.object_id
+    WHERE fk.name = 'FK_PurchaseOrderHeader_Employee_EmployeeID';
+    GO
+    ```
+
+    You should set the foreign key constraint to trusted if existing data in the table complies with the foreign key constraint. To set the foreign key to trusted, use the following script to trust the foreign key constraint again, noting the additional `WITH CHECK` syntax. Copy and paste the following example into the query window and select **Execute**.
+
+    ```sql
+    ALTER TABLE [Purchasing].[PurchaseOrderHeader] 
+    WITH CHECK 
+    CHECK CONSTRAINT FK_PurchaseOrderHeader_Employee_EmployeeID;
+    GO
+    ```
 
 ## Next steps
 
-- [ALTER TABLE &#40;Transact-SQL&#41;](../../t-sql/statements/alter-table-transact-sql.md).  
-  
+- [ALTER TABLE &#40;Transact-SQL&#41;](../../t-sql/statements/alter-table-transact-sql.md)
+- [View Foreign Key Properties](view-foreign-key-properties.md)

docs/relational-databases/tables/view-foreign-key-properties.md

@@ -1,8 +1,8 @@
 ---
-description: "View Foreign Key Properties"
-title: "View Foreign Key Properties | Microsoft Docs"
+description: "You can view the foreign key attributes of a relationship with SQL Server Management Studio or T-SQL queries."
+title: "View Foreign Key Properties"
 ms.custom: ""
-ms.date: "03/14/2017"
+ms.date: "04/13/2022"
 ms.prod: sql
 ms.prod_service: "database-engine, sql-database, synapse-analytics, pdw"
 ms.reviewer: ""
@@ -12,33 +12,16 @@ helpviewer_keywords:
   - "foreign keys [SQL Server], attributes"
   - "displaying foreign keys attributes"
   - "viewing foreign keys attributes"
-ms.assetid: b0e57cb7-9b26-4b96-b76a-1f59f5f498c5
 author: WilliamDAssafMSFT
 ms.author: wiassaf
 monikerRange: ">=aps-pdw-2016||=azuresqldb-current||=azure-sqldw-latest||>=sql-server-2016||>=sql-server-linux-2017||=azuresqldb-mi-current"
 ---
-# View Foreign Key Properties
+# View foreign key properties
 [!INCLUDE [sqlserver2016-asdb-asdbmi-asa-pdw](../../includes/applies-to-version/sqlserver2016-asdb-asdbmi-asa-pdw.md)]
 
   You can view the foreign key attributes of a relationship in [!INCLUDE[ssnoversion](../../includes/ssnoversion-md.md)] by using [!INCLUDE[ssManStudioFull](../../includes/ssmanstudiofull-md.md)] or [!INCLUDE[tsql](../../includes/tsql-md.md)].  
-  
- **In This Topic**  
-  
--   **Before you begin:**  
-  
-     [Security](#Security)  
-  
--   **To view the foreign key attributes of a specific table, using:**  
-  
-     [SQL Server Management Studio](#SSMSProcedure)  
-  
-     [Transact-SQL](#TsqlProcedure)  
-  
-##  <a name="BeforeYouBegin"></a> Before You Begin  
-  
-###  <a name="Security"></a> Security  
-  
-####  <a name="Permissions"></a> Permissions  
+
+###  <a name="Permissions"></a> Permissions  
  [!INCLUDE[ssCatViewPerm](../../includes/sscatviewperm-md.md)] For more information, see [Metadata Visibility Configuration](../../relational-databases/security/metadata-visibility-configuration.md).  
 
 ##  <a name="SSMSProcedure"></a> Using SQL Server Management Studio  
@@ -50,18 +33,19 @@ monikerRange: ">=aps-pdw-2016||=azuresqldb-current||=azure-sqldw-latest||>=sql-s
 2.  In the **Foreign Key Relationships** dialog box, select the relationship with properties you want to view.  
 
  If the foreign key columns are related to a primary key, the primary key columns are identified in **Table Designer** by a primary key symbol in the row selector.  
-  
+
+<a name="TsqlExample"></a>  
 ##  <a name="TsqlProcedure"></a> Using Transact-SQL  
 
 #### To view the foreign key attributes of a relationship in a specific table  
 
 1.  In **Object Explorer**, connect to an instance of [!INCLUDE[ssDE](../../includes/ssde-md.md)].  
 
-2.  On the Standard bar, click **New Query**.  
+2.  On the Standard bar, select **New Query**.  
 
-3.  Copy and paste the following example into the query window and click **Execute**. The example returns all foreign keys and their properties for the table `HumanResources.Employee` in the sample database.  
+3.  Copy and paste the following example into the query window and select **Execute**. The example returns all foreign keys and their properties for the table `HumanResources.Employee` in the sample database.  
 
-    ```  
+    ```sql  
     USE AdventureWorks2012;  
     GO  
     SELECT   
@@ -70,15 +54,19 @@ monikerRange: ">=aps-pdw-2016||=azuresqldb-current||=azure-sqldw-latest||>=sql-s
        ,COL_NAME(fc.parent_object_id, fc.parent_column_id) AS constraint_column_name  
        ,OBJECT_NAME (f.referenced_object_id) AS referenced_object  
        ,COL_NAME(fc.referenced_object_id, fc.referenced_column_id) AS referenced_column_name  
-       ,is_disabled  
-       ,delete_referential_action_desc  
-       ,update_referential_action_desc  
+       ,f.is_disabled, f.is_not_trusted
+       ,f.delete_referential_action_desc  
+       ,f.update_referential_action_desc  
     FROM sys.foreign_keys AS f  
     INNER JOIN sys.foreign_key_columns AS fc   
        ON f.object_id = fc.constraint_object_id   
     WHERE f.parent_object_id = OBJECT_ID('HumanResources.Employee');  
     ```  
 
  For more information, see [sys.foreign_keys &#40;Transact-SQL&#41;](../../relational-databases/system-catalog-views/sys-foreign-keys-transact-sql.md) and [sys.foreign_key_columns &#40;Transact-SQL&#41;](../../relational-databases/system-catalog-views/sys-foreign-key-columns-transact-sql.md).  
-  
-###  <a name="TsqlExample"></a>  
+
+## Next steps
+
+- [ALTER TABLE Statement](../../odbc/microsoft/alter-table-statement.md)
+- [Disable foreign key constraints for replication](disable-foreign-key-constraints-for-replication.md)
+- [Disable Foreign Key Constraints with INSERT and UPDATE Statements](disable-foreign-key-constraints-with-insert-and-update-statements.md)

docs/t-sql/data-types/ntext-text-and-image-transact-sql.md

@@ -1,8 +1,8 @@
 ---
-description: "ntext, text, and image (Transact-SQL)"
-title: "ntext, text, and image (Transact-SQL) | Microsoft Docs"
+description: "The ntext, text, and image data types are deprecated data types for storing large non-Unicode and Unicode character and binary data."
+title: "ntext, text, and image (Transact-SQL)"
 ms.custom: ""
-ms.date: "07/22/2017"
+ms.date: "04/13/2022"
 ms.prod: sql
 ms.prod_service: "database-engine, sql-database"
 ms.reviewer: ""
@@ -19,7 +19,6 @@ helpviewer_keywords:
   - "ntext data type"
   - "ntext data type, about ntext data type"
   - "image data type, about image data type"
-ms.assetid: b0d8769c-7598-4f97-8162-ace5f182b5bc
 author: MikeRayMSFT
 ms.author: mikeray
 ---
@@ -28,7 +27,8 @@ ms.author: mikeray
 
 Fixed and variable-length data types for storing large non-Unicode and Unicode character and binary data. Unicode data uses the UNICODE UCS-2 character set.
 
->**IMPORTANT!**  **ntext**, **text**, and **image** data types will be removed in a future version of SQL Server. Avoid using these data types in new development work, and plan to modify applications that currently use them. Use [nvarchar(max)](../../t-sql/data-types/nchar-and-nvarchar-transact-sql.md), [varchar(max)](../../t-sql/data-types/char-and-varchar-transact-sql.md), and [varbinary(max)](../../t-sql/data-types/binary-and-varbinary-transact-sql.md) instead.  
+> [!IMPORTANT]
+> The **ntext**, **text**, and **image** data types will be removed in a future version of SQL Server. Avoid using these data types in new development work, and plan to modify applications that currently use them. Use [nvarchar(max)](../../t-sql/data-types/nchar-and-nvarchar-transact-sql.md), [varchar(max)](../../t-sql/data-types/char-and-varchar-transact-sql.md), and [varbinary(max)](../../t-sql/data-types/binary-and-varbinary-transact-sql.md) instead.  
   
 ## Arguments
 **ntext**  
@@ -50,12 +50,18 @@ The following functions and statements can be used with **ntext**, **text**, or
 |[SUBSTRING (Transact-SQL)](../../t-sql/functions/substring-transact-sql.md)|[UPDATETEXT (Transact-SQL)](../../t-sql/queries/updatetext-transact-sql.md)|  
 |[TEXTPTR (Transact-SQL)](../../t-sql/functions/text-and-image-functions-textptr-transact-sql.md)|[WRITETEXT (Transact-SQL)](../../t-sql/queries/writetext-transact-sql.md)|  
 |[TEXTVALID (Transact-SQL)](../../t-sql/functions/text-and-image-functions-textvalid-transact-sql.md)||  
-  
+
+> [!CAUTION]
+> When dropping columns using the deprecated NTEXT data type, the cleanup of the deleted data occurs as a serialized operation on all rows. The cleanup can require a large amount of time. When dropping an NTEXT column in a table with lots of rows, update the NTEXT column to NULL value first, then drop the column. You can run this option with parallel operations and make it much faster.
+
 ## See also
-[CAST and CONVERT (Transact-SQL)](../../t-sql/functions/cast-and-convert-transact-sql.md)  
-[Data Type Conversion (Database Engine)](../../t-sql/data-types/data-type-conversion-database-engine.md)  
-[Data Types (Transact-SQL)](../../t-sql/data-types/data-types-transact-sql.md)  
-[LIKE (Transact-SQL)](../../t-sql/language-elements/like-transact-sql.md)  
-[SET @local_variable (Transact-SQL)](../../t-sql/language-elements/set-local-variable-transact-sql.md)  
-[Collation and Unicode Support](../../relational-databases/collations/collation-and-unicode-support.md)
+- [Data Types (Transact-SQL)](../../t-sql/data-types/data-types-transact-sql.md)  
+- [LIKE (Transact-SQL)](../../t-sql/language-elements/like-transact-sql.md)  
+- [SET @local_variable (Transact-SQL)](../../t-sql/language-elements/set-local-variable-transact-sql.md)  
+- [Collation and Unicode Support](../../relational-databases/collations/collation-and-unicode-support.md)
+
+## Next steps
 
+- [CAST and CONVERT (Transact-SQL)](../../t-sql/functions/cast-and-convert-transact-sql.md)  
+- [Data Type Conversion (Database Engine)](../../t-sql/data-types/data-type-conversion-database-engine.md)  
+- [ALTER TABLE (Transact-SQL)](../statements/alter-table-transact-sql.md)