C# 封装postSQL的添加，查询方法

Npgsql is the open source .NET data provider for PostgreSQL. It allows you to connect and interact with PostgreSQL server using .NET. ## Quickstart Here's a basic code snippet to get you started: ```csharp var connString = "Host=myserver;Username=mylogin;Password=mypass;Database=mydatabase"; await using var conn = new NpgsqlConnection(connString); await conn.OpenAsync(); // Insert some data await using (var cmd = new NpgsqlCommand("INSERT INTO data (some_field) VALUES (@p)", conn)) { cmd.Parameters.AddWithValue("p", "Hello world"); await cmd.ExecuteNonQueryAsync(); } // Retrieve all rows await using (var cmd = new NpgsqlCommand("SELECT some_field FROM data", conn)) await using (var reader = await cmd.ExecuteReaderAsync()) { while (await reader.ReadAsync()) Console.WriteLine(reader.GetString(0)); } ``` ## Key features * High-performance PostgreSQL driver. Regularly figures in the top contenders on the [TechEmpower Web Framework Benchmarks](https://www.techempower.com/benchmarks/). * Full support of most PostgreSQL types, including advanced ones such as arrays, enums, ranges, multiranges, composites, JSON, PostGIS and others. * Highly-efficient bulk import/export API. * Failover, load balancing and general multi-host support. * Great integration with Entity Framework Core via [Npgsql.EntityFrameworkCore.PostgreSQL](https://www.nuget.org/packages/Npgsql.EntityFrameworkCore.PostgreSQL). For the full documentation, please visit [the Npgsql website](https://www.npgsql.org). ## Related packages * The Entity Framework Core provider that works with this provider is [Npgsql.EntityFrameworkCore.PostgreSQL](https://www.nuget.org/packages/Npgsql.EntityFrameworkCore.PostgreSQL). * Spatial plugin to work with PostgreSQL PostGIS: [Npgsql.NetTopologySuite](https://www.nuget.org/packages/Npgsql.NetTopologySuite) * NodaTime plugin to use better date/time types with PostgreSQL: [Npgsql.NodaTime](https://www.nuget.org/packages/Npgsql.NodaTime) * OpenTelemetry support can be set up with [Npgsql.OpenTelemetry](https://www.nuget.org/packages/Npgsql.OpenTelemetry)