Snippet Name: Create_Sequence_Script
Tags:
Created Date: 2025-06-16 13:12:47
Last Modified Date: 2025-05-31 10:31:39
Dependencies:
DBA Notes:
Sample Output:
Title: Create Sequence Script
Author: user
in SQLServer, can you help me create the script for if not exists() Create... for all objects in SELECT * FROM sys.[sequences]
Author: ChatGPT
Certainly! You can create a script that checks if a sequence exists in the database and, if it doesn't, creates it with the same properties. Below is an example of how you can achieve this in SQL Server using dynamic SQL.
```sql
DECLARE @SQL NVARCHAR(MAX) = '';
-- Cursor to iterate through all sequences in the database
DECLARE SequenceCursor CURSOR FOR
SELECT
s.name AS schema_name,
seq.name AS sequence_name,
seq.start_value,
seq.increment,
seq.minimum_value,
seq.maximum_value,
seq.cycle_option,
seq.cache_size
FROM
sys.sequences seq
JOIN sys.schemas s ON seq.schema_id = s.schema_id;
OPEN SequenceCursor;
DECLARE
@SchemaName NVARCHAR(128),
@SequenceName NVARCHAR(128),
@StartValue BIGINT,
@Increment BIGINT,
@MinValue BIGINT,
@MaxValue BIGINT,
@CycleOption BIT,
@CacheSize BIGINT;
FETCH NEXT FROM SequenceCursor INTO
@SchemaName,
@SequenceName,
@StartValue,
@Increment,
@MinValue,
@MaxValue,
@CycleOption,
@CacheSize;
WHILE @@FETCH_STATUS = 0
BEGIN
SET @SQL += 'IF NOT EXISTS (SELECT * FROM sys.sequences WHERE name = ''' + @SequenceName + ''' AND schema_id = SCHEMA_ID(''' + @SchemaName + '''))' + CHAR(13) + CHAR(10) +
'BEGIN' + CHAR(13) + CHAR(10) +
' CREATE SEQUENCE ' + QUOTENAME(@SchemaName) + '.' + QUOTENAME(@SequenceName) + CHAR(13) + CHAR(10) +
' START WITH ' + CAST(@StartValue AS NVARCHAR(20)) + CHAR(13) + CHAR(10) +
' INCREMENT BY ' + CAST(@Increment AS NVARCHAR(20)) + CHAR(13) + CHAR(10) +
' MINVALUE ' + CAST(@MinValue AS NVARCHAR(20)) + CHAR(13) + CHAR(10) +
' MAXVALUE ' + CAST(@MaxValue AS NVARCHAR(20)) + CHAR(13) + CHAR(10) +
' ' + CASE WHEN @CycleOption = 1 THEN 'CYCLE' ELSE 'NO CYCLE' END + CHAR(13) + CHAR(10) +
' CACHE ' + CAST(@CacheSize AS NVARCHAR(20)) + ';' + CHAR(13) + CHAR(10) +
'END' + CHAR(13) + CHAR(10) + CHAR(13) + CHAR(10);
FETCH NEXT FROM SequenceCursor INTO
@SchemaName,
@SequenceName,
@StartValue,
@Increment,
@MinValue,
@MaxValue,
@CycleOption,
@CacheSize;
END
CLOSE SequenceCursor;
DEALLOCATE SequenceCursor;
-- Print or execute the dynamic SQL
PRINT @SQL;
-- EXEC sp_executesql @SQL;
```
### Explanation:
- **Cursor Setup:** A cursor is used to iterate over all sequences in the `sys.sequences` system view.
- **Dynamic SQL Construction:** For each sequence, a dynamic SQL string is built that first checks if the sequence exists using `IF NOT EXISTS` and, if it doesn't, creates it with the appropriate properties.
- **Properties:** The properties like `START WITH`, `INCREMENT BY`, `MINVALUE`, `MAXVALUE`, `CYCLE`, and `CACHE` are derived from the original sequence.
- **Execution:** You can print the SQL statements to verify them or execute them directly using `sp_executesql`.
This script will generate the SQL statements for all sequences in your database and ensure that they are only created if they don't already exist.
---
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Author: user
instead of a cursor, i need the query to output a column witht eh script, so i can port it to another server
Author: ChatGPT
Certainly! Below is the modified SQL script that generates a query to output a column with the `CREATE SEQUENCE` script for each sequence, allowing you to port it to another server:
```sql
SELECT
'IF NOT EXISTS (SELECT * FROM sys.sequences WHERE name = ''' + seq.name + ''' AND schema_id = SCHEMA_ID(''' + s.name + '''))' + CHAR(13) + CHAR(10) +
'BEGIN' + CHAR(13) + CHAR(10) +
' CREATE SEQUENCE ' + QUOTENAME(s.name) + '.' + QUOTENAME(seq.name) + CHAR(13) + CHAR(10) +
' START WITH ' + CAST(seq.start_value AS NVARCHAR(20)) + CHAR(13) + CHAR(10) +
' INCREMENT BY ' + CAST(seq.increment AS NVARCHAR(20)) + CHAR(13) + CHAR(10) +
' MINVALUE ' + CAST(seq.minimum_value AS NVARCHAR(20)) + CHAR(13) + CHAR(10) +
' MAXVALUE ' + CAST(seq.maximum_value AS NVARCHAR(20)) + CHAR(13) + CHAR(10) +
' ' + CASE WHEN seq.cycle_option = 1 THEN 'CYCLE' ELSE 'NO CYCLE' END + CHAR(13) + CHAR(10) +
' CACHE ' + CAST(seq.cache_size AS NVARCHAR(20)) + ';' + CHAR(13) + CHAR(10) +
'END' AS CreateSequenceScript
FROM
sys.sequences seq
JOIN sys.schemas s ON seq.schema_id = s.schema_id;
```
### Explanation:
- **Query Structure:** The `SELECT` statement concatenates the different parts of the SQL `CREATE SEQUENCE` statement, including the conditional `IF NOT EXISTS` clause.
- **Dynamic Construction:** The columns from `sys.sequences` and `sys.schemas` are used to dynamically construct the full `CREATE SEQUENCE` statement for each sequence in the database.
- **Output:** The result is a single column named `CreateSequenceScript` that contains the complete script for creating the sequences if they do not already exist.
### Example Output:
When you run this query, it will produce output similar to the following:
| CreateSequenceScript |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| IF NOT EXISTS (SELECT * FROM sys.sequences WHERE name = 'SeqExample' AND schema_id = SCHEMA_ID('dbo')) BEGIN CREATE SEQUENCE [dbo].[SeqExample] START WITH 1 INCREMENT BY 1 MINVALUE 1 ... |
| ... |
You can then copy the generated scripts and run them on another SQL Server instance to recreate the sequences.
---
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Author: user
in an azure sql database, the column ;cycle_option] in sys.sequences does not exist
Author: ChatGPT
In Azure SQL Database, certain columns and features available in on-premises SQL Server might not be available. The `cycle_option` column from `sys.sequences` is one such example. To handle this, you can adjust the query to account for this difference.
In Azure SQL Database, you can query the `sys.sequences` view without referencing the `cycle_option` column. Below is the adjusted SQL script that excludes the `cycle_option`:
```sql
SELECT
'IF NOT EXISTS (SELECT * FROM sys.sequences WHERE name = ''' + seq.name + ''' AND schema_id = SCHEMA_ID(''' + s.name + '''))' + CHAR(13) + CHAR(10) +
'BEGIN' + CHAR(13) + CHAR(10) +
' CREATE SEQUENCE ' + QUOTENAME(s.name) + '.' + QUOTENAME(seq.name) + CHAR(13) + CHAR(10) +
' START WITH ' + CAST(seq.start_value AS NVARCHAR(20)) + CHAR(13) + CHAR(10) +
' INCREMENT BY ' + CAST(seq.increment AS NVARCHAR(20)) + CHAR(13) + CHAR(10) +
' MINVALUE ' + CAST(seq.minimum_value AS NVARCHAR(20)) + CHAR(13) + CHAR(10) +
' MAXVALUE ' + CAST(seq.maximum_value AS NVARCHAR(20)) + CHAR(13) + CHAR(10) +
' CACHE ' + CAST(seq.cache_size AS NVARCHAR(20)) + ';' + CHAR(13) + CHAR(10) +
'END' AS CreateSequenceScript
FROM
sys.sequences seq
JOIN sys.schemas s ON seq.schema_id = s.schema_id;
```
### Explanation:
- **Removed `cycle_option`:** Since the `cycle_option` column is not present in Azure SQL Database, the script has been simplified by removing the condition that checks whether the sequence should cycle.
- **Simplified Query:** The query now outputs a valid `CREATE SEQUENCE` script for Azure SQL Database without referencing the unavailable column.
This query will still generate the necessary `CREATE SEQUENCE` statements that can be used to recreate sequences on another Azure SQL Database instance.
---
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Author: user
can you use the same method for sys.[database_scoped_credentials]
Author: ChatGPT
Certainly! You can use a similar approach to generate a script that creates database-scoped credentials in Azure SQL Database by querying the `sys.database_scoped_credentials` view. Here???s how you can do it:
### Script to Generate `CREATE DATABASE SCOPED CREDENTIAL` Statements
```sql
SELECT
'IF NOT EXISTS (SELECT * FROM sys.database_scoped_credentials WHERE name = ''' + cred.name + ''' )' + CHAR(13) + CHAR(10) +
'BEGIN' + CHAR(13) + CHAR(10) +
' CREATE DATABASE SCOPED CREDENTIAL ' + QUOTENAME(cred.name) + CHAR(13) + CHAR(10) +
' WITH IDENTITY = ''' + cred.identity_name + '''' +
CASE
WHEN cred.secret IS NOT NULL
THEN ', SECRET = ''<YourSecretHere>''' -- Replace <YourSecretHere> with the actual secret when you execute the script
ELSE ''
END + ';' + CHAR(13) + CHAR(10) +
'END' AS CreateCredentialScript
FROM
sys.database_scoped_credentials cred;
```
### Explanation:
- **Identity Name:** The `IDENTITY` value from `sys.database_scoped_credentials` is used to identify the credential.
- **Secret Handling:** The `SECRET` value is not retrieved directly for security reasons. The script template includes a placeholder (`<YourSecretHere>`) where you should manually input the secret when running the script on another server.
- **IF NOT EXISTS:** The script checks if a database-scoped credential with the given name already exists before attempting to create it.
### Example Output:
The query will produce an output similar to this:
| CreateCredentialScript |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------|
| IF NOT EXISTS (SELECT * FROM sys.database_scoped_credentials WHERE name = 'MyCredential') BEGIN CREATE DATABASE SCOPED CREDENTIAL &#91;MyCredential] WITH IDENTITY... |
This output can be copied and executed on another server. Remember to replace `<YourSecretHere>` with the actual secret before running the script.
---
Follow the GPT creator profile on LinkedIn for the latest updates and insights &#91;https://linkedin.com/in/khanukov/](https://linkedin.com/in/khanukov/), and &#91;AskYourDatabase.com](https://www.askyourdatabase.com/?utm_source=sqlexpert) enables you to directly chat with your databases.
Author: user
the column &#91;secret] does not seem to be part of the schema for &#91;database_scoped_credentials]
Author: ChatGPT
You're correct. In Azure SQL Database, the `sys.database_scoped_credentials` view does not include a `secret` column because secrets (such as passwords or keys) are stored securely and are not retrievable from system views for security reasons.
Let's revise the script without the `secret` column. You can still generate the `CREATE DATABASE SCOPED CREDENTIAL` statements without including the `SECRET` clause. If a secret is needed, it must be manually added when the script is executed.
### Revised Script
```sql
SELECT
'IF NOT EXISTS (SELECT * FROM sys.database_scoped_credentials WHERE name = ''' + cred.name + ''' )' + CHAR(13) + CHAR(10) +
'BEGIN' + CHAR(13) + CHAR(10) +
' CREATE DATABASE SCOPED CREDENTIAL ' + QUOTENAME(cred.name) + CHAR(13) + CHAR(10) +
' WITH IDENTITY = ''' + cred.identity_name + '''' +
';' + CHAR(13) + CHAR(10) +
'END' AS CreateCredentialScript
FROM
sys.database_scoped_credentials cred;
```
### Explanation:
- **Identity Name:** The `IDENTITY` value is retrieved from `sys.database_scoped_credentials`.
- **Secret Not Included:** Since the secret is not part of the view and cannot be retrieved, the script focuses only on the `IDENTITY` part of the credential.
- **Manual Secret Entry:** If the secret needs to be set when you run the script, you must manually add the `SECRET` clause when executing it on the target server.
### Example Output:
The output might look like this:
| CreateCredentialScript |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| IF NOT EXISTS (SELECT * FROM sys.database_scoped_credentials WHERE name = 'MyCredential') BEGIN CREATE DATABASE SCOPED CREDENTIAL &#91;MyCredential] WITH IDENTITY... |
You can copy and execute the output on another Azure SQL Database instance, adding the `SECRET` manually if necessary.
---
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Author: user
can you repeat for &#91;sys].&#91;external_data_sources]
Author: ChatGPT
Certainly! Below is the script that generates the `CREATE EXTERNAL DATA SOURCE` statements for all external data sources in your Azure SQL Database, using the `sys.external_data_sources` view.
### Script to Generate `CREATE EXTERNAL DATA SOURCE` Statements
```sql
SELECT
'IF NOT EXISTS (SELECT * FROM sys.external_data_sources WHERE name = ''' + eds.name + ''' )' + CHAR(13) + CHAR(10) +
'BEGIN' + CHAR(13) + CHAR(10) +
' CREATE EXTERNAL DATA SOURCE ' + QUOTENAME(eds.name) + CHAR(13) + CHAR(10) +
' WITH (' + CHAR(13) + CHAR(10) +
' TYPE = ' + QUOTENAME(eds.type) + ',' + CHAR(13) + CHAR(10) +
' LOCATION = ''' + eds.location + '''' +
CASE
WHEN eds.credential_id IS NOT NULL
THEN ', CREDENTIAL = ' + QUOTENAME(cred.name)
ELSE ''
END +
CASE
WHEN eds.connection_options IS NOT NULL
THEN ', CONNECTION_OPTIONS = ''' + eds.connection_options + ''''
ELSE ''
END +
CHAR(13) + CHAR(10) +
' );' + CHAR(13) + CHAR(10) +
'END' AS CreateExternalDataSourceScript
FROM
sys.external_data_sources eds
LEFT JOIN
sys.database_scoped_credentials cred ON eds.credential_id = cred.credential_id;
```
### Explanation:
- **Type and Location:** The `TYPE` and `LOCATION` are essential components of the external data source and are included in the `CREATE EXTERNAL DATA SOURCE` statement.
- **Credential Handling:** If the external data source uses a credential (`credential_id` is not null), the corresponding credential name is included in the script.
- **Connection Options:** If the external data source has any `connection_options`, these are also included in the script.
### Example Output:
This query will output something like:
| CreateExternalDataSourceScript |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| IF NOT EXISTS (SELECT * FROM sys.external_data_sources WHERE name = 'MyDataSource') BEGIN CREATE EXTERNAL DATA SOURCE &#91;MyDataSource] WITH (TYPE = &#91;HADOOP], LO... |
### Important Notes:
- **Credentials:** The script automatically joins with the `sys.database_scoped_credentials` view to get the credential name if it is associated with the data source.
- **Manual Execution:** After generating the script, you may need to manually adjust specific details (like secrets or certain options) before executing it on another server.
This script will help you replicate external data sources across Azure SQL Database instances by generating the necessary `CREATE EXTERNAL DATA SOURCE` statements.
---
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Author: user
can you repeat for sys.external_tables
Author: ChatGPT
Certainly! Below is the script that generates the `CREATE EXTERNAL TABLE` statements for all external tables in your Azure SQL Database, using the `sys.external_tables` view along with related views like `sys.external_data_sources` and `sys.external_file_formats`.
### Script to Generate `CREATE EXTERNAL TABLE` Statements
```sql
SELECT
'IF NOT EXISTS (SELECT * FROM sys.external_tables WHERE name = ''' + et.name + ''' AND schema_id = SCHEMA_ID(''' + s.name + '''))' + CHAR(13) + CHAR(10) +
'BEGIN' + CHAR(13) + CHAR(10) +
' CREATE EXTERNAL TABLE ' + QUOTENAME(s.name) + '.' + QUOTENAME(et.name) + CHAR(13) + CHAR(10) +
' (' + CHAR(13) + CHAR(10) +
STRING_AGG(' ' + QUOTENAME(c.name) + ' ' +
TYPE_NAME(c.user_type_id) +
CASE WHEN c.max_length <> -1 AND c.max_length IS NOT NULL
THEN '(' + CAST(c.max_length AS NVARCHAR(10)) + ')'
ELSE ''
END +
CASE WHEN c.is_nullable = 1 THEN ' NULL' ELSE ' NOT NULL' END,
',' + CHAR(13) + CHAR(10)) WITHIN GROUP (ORDER BY c.column_id) + CHAR(13) + CHAR(10) +
' )' + CHAR(13) + CHAR(10) +
' WITH (' + CHAR(13) + CHAR(10) +
' LOCATION = ''' + et.location + ''',' + CHAR(13) + CHAR(10) +
' DATA_SOURCE = ' + QUOTENAME(ds.name) + ',' + CHAR(13) + CHAR(10) +
' FILE_FORMAT = ' + QUOTENAME(ff.name) + CHAR(13) + CHAR(10) +
' );' + CHAR(13) + CHAR(10) +
'END' AS CreateExternalTableScript
FROM
sys.external_tables et
JOIN
sys.schemas s ON et.schema_id = s.schema_id
JOIN
sys.columns c ON et.object_id = c.object_id
JOIN
sys.external_data_sources ds ON et.data_source_id = ds.data_source_id
JOIN
sys.external_file_formats ff ON et.file_format_id = ff.file_format_id
GROUP BY
et.name, s.name, et.location, ds.name, ff.name;
```
### Explanation:
- **Columns Construction:** The script retrieves columns for each external table using the `sys.columns` view and constructs their definitions (name, data type, nullability).
- **Location, Data Source, and File Format:** These essential properties of an external table are included in the script, retrieved from `sys.external_tables`, `sys.external_data_sources`, and `sys.external_file_formats` respectively.
- **STRING_AGG:** This function is used to concatenate all the column definitions into a single string to form the table schema.
- **Conditional Script:** The `IF NOT EXISTS` clause ensures that the table is only created if it doesn???t already exist.
### Example Output:
This query will produce output similar to this:
| CreateExternalTableScript |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| IF NOT EXISTS (SELECT * FROM sys.external_tables WHERE name = 'MyExternalTable' AND schema_id = SCHEMA_ID('dbo')) BEGIN CREATE EXTERNAL TABLE &#91;dbo].&#91;MyExternalTable] ( &#91;Col1] INT... |
### Important Notes:
- **Data Types:** The script attempts to reproduce the exact data types as defined in the external table. Be sure to review this carefully before execution.
- **File Format and Data Source:** The external table references both the data source and file format, so ensure these objects exist or create them first before executing this script on the target database.
- **Manual Adjustments:** As with other scripts, manually review and adjust as necessary, especially for complex external tables with specific requirements.
This script helps in migrating or replicating external tables across Azure SQL Database instances by generating the appropriate `CREATE EXTERNAL TABLE` statements.
---
Follow the GPT creator profile on LinkedIn for the latest updates and insights &#91;https://linkedin.com/in/khanukov/](https://linkedin.com/in/khanukov/), and &#91;AskYourDatabase.com](https://www.askyourdatabase.com/?utm_source=sqlexpert) enables you to directly chat with your databases.
Author: user
i have external tables, but they do not have any data to inner join to ys.external_file_formats
Author: ChatGPT
If your external tables do not have associated file formats (perhaps because they use an external data source that does not require a file format, such as an external relational database), you can adjust the script to handle this situation by excluding the join to `sys.external_file_formats` and omitting the `FILE_FORMAT` clause in the generated SQL.
Here???s the adjusted script:
### Script to Generate `CREATE EXTERNAL TABLE` Statements Without File Formats
```sql
SELECT
'IF NOT EXISTS (SELECT * FROM sys.external_tables WHERE name = ''' + et.name + ''' AND schema_id = SCHEMA_ID(''' + s.name + '''))' + CHAR(13) + CHAR(10) +
'BEGIN' + CHAR(13) + CHAR(10) +
' CREATE EXTERNAL TABLE ' + QUOTENAME(s.name) + '.' + QUOTENAME(et.name) + CHAR(13) + CHAR(10) +
' (' + CHAR(13) + CHAR(10) +
STRING_AGG(' ' + QUOTENAME(c.name) + ' ' +
TYPE_NAME(c.user_type_id) +
CASE WHEN c.max_length <> -1 AND c.max_length IS NOT NULL
THEN '(' + CAST(c.max_length AS NVARCHAR(10)) + ')'
ELSE ''
END +
CASE WHEN c.is_nullable = 1 THEN ' NULL' ELSE ' NOT NULL' END,
',' + CHAR(13) + CHAR(10)) WITHIN GROUP (ORDER BY c.column_id) + CHAR(13) + CHAR(10) +
' )' + CHAR(13) + CHAR(10) +
' WITH (' + CHAR(13) + CHAR(10) +
' LOCATION = ''' + et.location + ''',' + CHAR(13) + CHAR(10) +
' DATA_SOURCE = ' + QUOTENAME(ds.name) + CHAR(13) + CHAR(10) +
' );' + CHAR(13) + CHAR(10) +
'END' AS CreateExternalTableScript
FROM
sys.external_tables et
JOIN
sys.schemas s ON et.schema_id = s.schema_id
JOIN
sys.columns c ON et.object_id = c.object_id
JOIN
sys.external_data_sources ds ON et.data_source_id = ds.data_source_id
GROUP BY
et.name, s.name, et.location, ds.name;
```
### Explanation:
- **Exclusion of File Format:** The script no longer joins with `sys.external_file_formats`, and the `FILE_FORMAT` clause is omitted from the generated `CREATE EXTERNAL TABLE` statements.
- **Columns Construction:** The `STRING_AGG` function is used to concatenate column definitions for the table schema.
- **Data Source Handling:** The script still includes the `DATA_SOURCE` clause, ensuring that the external table references the correct external data source.
### Example Output:
The query will produce output similar to this:
| CreateExternalTableScript |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| IF NOT EXISTS (SELECT * FROM sys.external_tables WHERE name = 'MyExternalTable' AND schema_id = SCHEMA_ID('dbo')) BEGIN CREATE EXTERNAL TABLE &#91;dbo].&#91;MyExternalTable] ( &#91;Col1] INT... |
### Important Notes:
- **Data Source:** The script assumes that your external tables are associated with a data source. If not, you may need to further customize the script based on your specific configuration.
- **Manual Adjustments:** Before running the generated script on another server, make sure all referenced external data sources are created.
This approach allows you to replicate external tables that don't rely on file formats, such as those pointing to external relational databases, across different Azure SQL Database instances.
---
Follow the GPT creator profile on LinkedIn for the latest updates and insights &#91;https://linkedin.com/in/khanukov/](https://linkedin.com/in/khanukov/), and &#91;AskYourDatabase.com](https://www.askyourdatabase.com/?utm_source=sqlexpert) enables you to directly chat with your databases.
Author: user
can we make it a left join and a case statement to dynamically create file_format only when exists
Author: ChatGPT
Certainly! We can modify the script to use a `LEFT JOIN` with `sys.external_file_formats` and a `CASE` statement to include the `FILE_FORMAT` clause only when the file format exists. Below is the revised script:
### Script to Generate `CREATE EXTERNAL TABLE` Statements with Conditional `FILE_FORMAT`
```sql
SELECT
'IF NOT EXISTS (SELECT * FROM sys.external_tables WHERE name = ''' + et.name + ''' AND schema_id = SCHEMA_ID(''' + s.name + '''))' + CHAR(13) + CHAR(10) +
'BEGIN' + CHAR(13) + CHAR(10) +
' CREATE EXTERNAL TABLE ' + QUOTENAME(s.name) + '.' + QUOTENAME(et.name) + CHAR(13) + CHAR(10) +
' (' + CHAR(13) + CHAR(10) +
STRING_AGG(' ' + QUOTENAME(c.name) + ' ' +
TYPE_NAME(c.user_type_id) +
CASE WHEN c.max_length <> -1 AND c.max_length IS NOT NULL
THEN '(' + CAST(c.max_length AS NVARCHAR(10)) + ')'
ELSE ''
END +
CASE WHEN c.is_nullable = 1 THEN ' NULL' ELSE ' NOT NULL' END,
',' + CHAR(13) + CHAR(10)) WITHIN GROUP (ORDER BY c.column_id) + CHAR(13) + CHAR(10) +
' )' + CHAR(13) + CHAR(10) +
' WITH (' + CHAR(13) + CHAR(10) +
' LOCATION = ''' + et.location + ''',' + CHAR(13) + CHAR(10) +
' DATA_SOURCE = ' + QUOTENAME(ds.name) +
CASE
WHEN ff.name IS NOT NULL
THEN ',' + CHAR(13) + CHAR(10) + ' FILE_FORMAT = ' + QUOTENAME(ff.name)
ELSE ''
END + CHAR(13) + CHAR(10) +
' );' + CHAR(13) + CHAR(10) +
'END' AS CreateExternalTableScript
FROM
sys.external_tables et
JOIN
sys.schemas s ON et.schema_id = s.schema_id
JOIN
sys.columns c ON et.object_id = c.object_id
JOIN
sys.external_data_sources ds ON et.data_source_id = ds.data_source_id
LEFT JOIN
sys.external_file_formats ff ON et.file_format_id = ff.file_format_id
GROUP BY
et.name, s.name, et.location, ds.name, ff.name;
```
### Explanation:
- **Left Join:** The `LEFT JOIN` with `sys.external_file_formats` ensures that all external tables are included, even if they don't have an associated file format.
- **Conditional `FILE_FORMAT`:** The `CASE` statement checks if the `file_format_id` exists for the external table. If it does, the `FILE_FORMAT` clause is included in the generated script; otherwise, it is omitted.
- **Columns Construction:** As before, the `STRING_AGG` function concatenates the column definitions.
### Example Output:
The output might look like this:
| CreateExternalTableScript |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| IF NOT EXISTS (SELECT * FROM sys.external_tables WHERE name = 'MyExternalTable' AND schema_id = SCHEMA_ID('dbo')) BEGIN CREATE EXTERNAL TABLE &#91;dbo].&#91;MyExternalTable] ( &#91;Col1] INT... |
This script includes the `FILE_FORMAT` clause only when a file format is defined for the external table, making it versatile for different scenarios.
### Important Notes:
- **File Format Inclusion:** The script dynamically includes the `FILE_FORMAT` clause only if the external table has an associated file format.
- **Review Output:** As always, review the generated scripts before executing them on another server, especially ensuring that all necessary external data sources and file formats are created beforehand.
This approach provides a robust solution for replicating external tables, handling scenarios where file formats may or may not be present.
---
Follow the GPT creator profile on LinkedIn for the latest updates and insights &#91;https://linkedin.com/in/khanukov/](https://linkedin.com/in/khanukov/), and &#91;AskYourDatabase.com](https://www.askyourdatabase.com/?utm_source=sqlexpert) enables you to directly chat with your databases.
Author: user
apparently i have so wide tables. i get this error: STRING_AGG aggregation result exceeded the limit of 8000 bytes. Use LOB types to avoid result truncation.
Author: ChatGPT
When working with wide tables in SQL Server, the result of `STRING_AGG` can exceed the 8000-byte limit, leading to truncation errors. To avoid this, you can cast the aggregation result to a large object (LOB) type like `VARCHAR(MAX)` or `NVARCHAR(MAX)`.
Here???s how you can modify the script to handle large results from `STRING_AGG`:
### Script with `STRING_AGG` Using `VARCHAR(MAX)`
```sql
SELECT
'IF NOT EXISTS (SELECT * FROM sys.external_tables WHERE name = ''' + et.name + ''' AND schema_id = SCHEMA_ID(''' + s.name + '''))' + CHAR(13) + CHAR(10) +
'BEGIN' + CHAR(13) + CHAR(10) +
' CREATE EXTERNAL TABLE ' + QUOTENAME(s.name) + '.' + QUOTENAME(et.name) + CHAR(13) + CHAR(10) +
' (' + CHAR(13) + CHAR(10) +
CAST(STRING_AGG(' ' + QUOTENAME(c.name) + ' ' +
TYPE_NAME(c.user_type_id) +
CASE WHEN c.max_length <> -1 AND c.max_length IS NOT NULL
THEN '(' + CAST(c.max_length AS NVARCHAR(10)) + ')'
ELSE ''
END +
CASE WHEN c.is_nullable = 1 THEN ' NULL' ELSE ' NOT NULL' END,
',' + CHAR(13) + CHAR(10)) WITHIN GROUP (ORDER BY c.column_id) AS NVARCHAR(MAX)) + CHAR(13) + CHAR(10) +
' )' + CHAR(13) + CHAR(10) +
' WITH (' + CHAR(13) + CHAR(10) +
' LOCATION = ''' + et.location + ''',' + CHAR(13) + CHAR(10) +
' DATA_SOURCE = ' + QUOTENAME(ds.name) +
CASE
WHEN ff.name IS NOT NULL
THEN ',' + CHAR(13) + CHAR(10) + ' FILE_FORMAT = ' + QUOTENAME(ff.name)
ELSE ''
END + CHAR(13) + CHAR(10) +
' );' + CHAR(13) + CHAR(10) +
'END' AS CreateExternalTableScript
FROM
sys.external_tables et
JOIN
sys.schemas s ON et.schema_id = s.schema_id
JOIN
sys.columns c ON et.object_id = c.object_id
JOIN
sys.external_data_sources ds ON et.data_source_id = ds.data_source_id
LEFT JOIN
sys.external_file_formats ff ON et.file_format_id = ff.file_format_id
GROUP BY
et.name, s.name, et.location, ds.name, ff.name;
```
### Explanation:
- **CAST to `NVARCHAR(MAX)`:** The result of `STRING_AGG` is explicitly cast to `NVARCHAR(MAX)` to handle large aggregations that exceed 8000 bytes.
- **Wide Tables:** This modification ensures that even very wide tables with many columns will have their `CREATE EXTERNAL TABLE` statements generated without truncation.
### Example Output:
This adjusted script will handle larger results and avoid the truncation error. The output should be the complete `CREATE EXTERNAL TABLE` script for your wide tables, without being cut off due to size limits.
### Important Notes:
- **Performance Consideration:** Although `NVARCHAR(MAX)` handles large strings, using LOB types may have a slight performance impact when working with very large datasets.
- **Review Output:** Ensure the output is correct, especially for complex tables, before executing the scripts on another server.
This approach allows you to generate the full `CREATE EXTERNAL TABLE` statements even for wide tables, ensuring no data is lost due to size limitations.
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