This repository contains the Azure SQL bindings for Azure Functions extension code as well as a quick start tutorial and samples illustrating how to use the binding in different ways. The types of bindings supported are:
- **Input Binding**: takes a SQL query to run and returns the output of the query in the function.
- **Output Binding**: takes a list of rows and upserts them into the user table (i.e. If a row doesn't already exist, it is added. If it does, it is updated).
- **Trigger Binding**: monitors the user table for changes (i.e., row inserts, updates, and deletes) and invokes the function with updated rows.
Further information on the Azure SQL binding for Azure Functions is also available in the [Azure Functions docs](https://docs.microsoft.com/azure/azure-functions/functions-bindings-azure-sql).
This extension uses the [OPENJSON](https://learn.microsoft.com/sql/t-sql/functions/openjson-transact-sql) statement which requires a database compatibility level of 130 or higher (2016 or higher). To view or change the compatibility level of your database, see [this documentation article](https://learn.microsoft.com/sql/relational-databases/databases/view-or-change-the-compatibility-level-of-a-database) for more information.
Databases on SQL Server, Azure SQL Database, or Azure SQL Managed Instance which meet the compatibility level requirement above are supported.
- Output bindings against tables with columns of data types `NTEXT`, `TEXT`, or `IMAGE` are not supported and data upserts will fail. These types [will be removed](https://docs.microsoft.com/sql/t-sql/data-types/ntext-text-and-image-transact-sql) in a future version of SQL Server and are not compatible with the `OPENJSON` function used by this Azure Functions binding.
- Output bindings execution order is not deterministic ([azure-webjobs-sdk#1025](https://github.com/Azure/azure-webjobs-sdk/issues/1025)) and so the order that data is upserted is not guaranteed. This can be problematic if, for example, you upsert rows to two separate tables with one having a foreign key reference to another. The upsert will fail if the dependent table does its upsert first.
Some options for working around this :
* Have multiple functions, with dependent functions being triggered by the initial functions (through a trigger binding or other such method)
* Use [dynamic (imperative)](https://learn.microsoft.com/azure/azure-functions/functions-bindings-expressions-patterns#binding-at-runtime) bindings (.NET only)
* Use [IAsyncCollector](https://learn.microsoft.com/azure/azure-functions/functions-dotnet-class-library?tabs=v2%2Ccmd#writing-multiple-output-values) and call `FlushAsync` in the order desired (.NET only)
- For Java Functions using Output bindings against a table with columns of data types 'DATETIME', 'DATETIME2', or 'SMALLDATETIME', use java.util.Date type to ensure the datetime is formatted correctly.
- Trigger bindings will exhibit undefined behavior if the SQL table schema gets modified while the user application is running, for example, if a column is added, renamed or deleted or if the primary key is modified or deleted. In such cases, restarting the application should help resolve any errors.
This extension collect usage data in order to help us improve your experience. The data is anonymous and doesn't include any personal information. You can opt-out of telemetry by setting the `AZUREFUNCTIONS_SQLBINDINGS_TELEMETRY_OPTOUT` environment variable or the `AzureFunctionsSqlBindingsTelemetryOptOut` app setting (in your `*.settings.json` file) to '1', 'true' or 'yes';
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