sql-insert

SqlParameterCollection only accepts non-null SqlParameter type objects, not SqlParameter objects

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When you try to execute a query with EF Core that has parameters, you get the following exception: System.InvalidCastException: The SqlParameterCollection only accepts non-null SqlParameter type objects, not SqlParameter objects The error message is confusing because it’s not showing the full type names. This error means you’re using System.Data.SqlClient.SqlParameter, but EF Core only accepts Microsoft.Data.SqlClient.SqlParameter. … Read more

C# – Use SqlDbType.Structured for table parameters

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To use a table-valued parameter (TVP) with SqlCommand (ADO.NET), pass in a DataTable as a SqlDbType.Structured parameter, like this: I’ll show a full example, starting with creating a TVP type and then inserting it as a SqlDbType.Structured parameter as shown above. 1 – Create the TVP type in SQL Server To be able to pass … Read more

SQL Server – Copy data from one table to another

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To copy data from one table to an existing table, use INSERT INTO SELECT and specify the column list: If the columns are the exact same in the two tables (and there are no identity columns), you don’t need to specify the column list: When the table doesn’t exist, use SELECT INTO, specifying which columns … Read more

C# – Get inserted identity value with Dapper

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When you insert a record into a table with an identity column, the value for the identity column is automatically generated for you. The simplest way to get the inserted identity value is to put OUTPUT INSERTED.<identity column name> in the insert statement: To get the output value with Dapper, use ExecuteScalar<int>(): This inserts the … Read more

EF Core – Inheritance mapping

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There are two ways to do inheritance mapping in EF Core: Let’s say we have a database with employees. All employees have an id and a name. There are currently two types of employees: programmers and drivers. Programmers have a language (ex: C#), and drivers have a car (ex: Honda). We can model this with … Read more

C# – Table-valued parameters (TVP) with Dapper

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Table-valued parameters (TVP) allow you to send multiple rows of data as a parameter into SQL queries. This is useful for SELECTs and INSERTs. In this article, I’ll show how to create a TVP in SQL Server and then use it in queries with Dapper. 1 – Create the TVP in SQL Server To be … Read more

SQL Server – Getting and storing date/time

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In this article, I’ll show built-in functions in SQL Server for getting the current datetime and how to get individual parts of the datetime (such as the year). Then show I’ll show how to store datetimes using the four different date/time data types (date, time, datetime2, and datetimeoffset). Getting the current datetime SQL Server has … Read more

C# – SQL Bulk Insert with SqlBulkCopy

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When you need to insert multiple rows into the database, consider doing a Bulk Insert instead of inserting one row at a time. Bulk Insertions are up to 20x faster than executing SQL Insert repeatedly. The simplest way to do a SQL Bulk Insert is by using the built-in SqlBulkCopy (from System.Data.SqlClient) with a DataTable. … Read more

Modifying JSON in SQL Server

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There are two ways to modify JSON data in a SQL Server table: In this article, I’ll show how to insert, update, and delete JSON data by using the JSON_MODIFY() function. I’ll also show how to deal with JSON arrays. Note: This is part 2 of the mini-series about the SQL Server JSON API. The … Read more

Querying JSON in SQL Server

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In SQL Server 2016, Microsoft added support for handling JSON data: The JSON API in SQL Server is well-suited for simple scenarios where you only need to do basic querying and manipulation. For advanced querying, the SQL Server JSON API gets complicated and hard to use, so you may want to look into other options. … Read more

Using sp_msForeachTable in SQL Server

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You can use the sp_msForeachTable stored proc in SQL Server to execute a query/command against all tables in the database. To give you an idea about how to use this, here’s an example of using it to do a SELECT query against all tables: Internally, sp_msForeachTable gets all user table names (from dbo.sysobjects) and opens … Read more

SqlTypeException: SqlDateTime overflow

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Problem I am executing a SQL query and trying to set a datetime column to DateTime.MinValue. I’m getting the following exception: System.Data.SqlTypes.SqlTypeException: ‘SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM.’ The problem is that DateTime.MinValue is 1/1/0001 12:00:00 AM and the SQL Server DateTime minimum value is 1/1/1753 12:00 AM. Solution … Read more

C# – Monitor data changes with SQL Server query notifications

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You can use SQL Server query notifications to send push notifications to your code when data changes. This is an alternative to polling the database for changes. In this article, I’ll show how to configure this feature and work with it in the code. 1 – Enable Service Broker and configure permissions You need to … Read more

Find the distance between two coordinates using SQL and C#

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Imagine you’re in the middle of Millennium Park in Chicago. You want some coffee, but want a good deal on it. You open an app and see the nearest coffee shops offering deals to anyone with this app. How did this app know the distance from you to the coffee shops? This article will show … Read more

SQL – Sort into groups, then sort within groups

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I recently came across a complex sorting problem that required sorting the data into groups, then further sorting the data within each group. I’ll explain this problem with a concrete example, and then I’ll show the SQL query I used to solve the problem. Let’s say we have orders, departments, and users. Users can be … Read more