标签:transaction data 读写 分离 query Dapper null type public
在上一篇说了封闭Dapper扩展方法为一个接口来支持Mock,接下来看看如何实现读写分离。
其实定义两个接口,一个用来实现读,一个用来实现写。在读的接口里只有Query的方法,在写的接口里实现Query和Execute全量(通读写的库也是支持读的,有的场景还是必须在写库里读,因为写库往读库中同步时是有时差的)。
IDapperPlusRead.cs
/// <summary> /// DapperPlus读接口 /// </summary> public interface IDapperPlusRead { /// <summary> /// 连接 /// </summary> public IDbConnection Connection { get; } /// <summary> /// Executes a single-row query, returning the data typed as type. /// </summary> /// <param name="type">The type to return.</param> /// <param name="sql">The SQL to execute for the query.</param> /// <param name="param">The parameters to pass, if any.</param> /// <param name="transaction">The transaction to use, if any.</param> /// <param name="buffered">Whether to buffer results in memory.</param> /// <param name="commandTimeout">The command timeout (in seconds).</param> /// <param name="commandType">The type of command to execute.</param> /// <returns>A sequence of data of the supplied type; if a basic type(int, string, etc) is queried then the data from the first column in assumed, otherwise an instance is created per row, and a direct column-name===member-name mapping is assumed(case insensitive). /// 异常:T:System.ArgumentNullException:type is null. /// </returns> IEnumerable<object> Query(Type type, string sql, object param = null, IDbTransaction transaction = null, bool buffered = true, int? commandTimeout = null, CommandType? commandType = null); //这时省略n个方法 }
IDapperPlusWrite.cs
/// <summary> /// 写Dapper接口 /// </summary> public interface IDapperPlusWrite { /// <summary> /// 连接 /// </summary> public IDbConnection Connection { get; } /// <summary> /// Execute parameterized SQL. /// </summary> /// <param name="sql">The SQL to execute for this query.</param> /// <param name="param">The parameters to use for this query.</param> /// <param name="transaction">The transaction to use for this query.</param> /// <param name="commandTimeout">Number of seconds before command execution timeout.</param> /// <param name="commandType">Is it a stored proc or a batch?</param> /// <returns>The number of rows affected.</returns> int Execute(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null); /// <summary> /// Executes a single-row query, returning the data typed as type. /// </summary> /// <param name="type">The type to return.</param> /// <param name="sql">The SQL to execute for the query.</param> /// <param name="param">The parameters to pass, if any.</param> /// <param name="transaction">The transaction to use, if any.</param> /// <param name="buffered">Whether to buffer results in memory.</param> /// <param name="commandTimeout">The command timeout (in seconds).</param> /// <param name="commandType">The type of command to execute.</param> /// <returns>A sequence of data of the supplied type; if a basic type(int, string, etc) is queried then the data from the first column in assumed, otherwise an instance is created per row, and a direct column-name===member-name mapping is assumed(case insensitive). /// 异常:T:System.ArgumentNullException:type is null. /// </returns> IEnumerable<object> Query(Type type, string sql, object param = null, IDbTransaction transaction = null, bool buffered = true, int? commandTimeout = null, CommandType? commandType = null); //这时省略n个方法 }
按照读写接口实现各自的类,这里就要在两个类的构造里取出各自己的连接字符串(读写库的实例或库名有所区别),这里用了个约定,就是在配置里,连接字符串的名称有read或write字样,通过这个约定来分别取读写连接字符串。
DapperPlusRead.cs
/// <summary> /// DapperPlus读实现类 /// </summary> public class DapperPlusRead : IDapperPlusRead { protected IDbConnection _connection; /// <summary> /// 构造 /// </summary> /// <param name="connection">连接</param> /// <param name="configuration">配置</param> public DapperPlusRead(IDbConnection connection, IConfiguration configuration) { var connectionStrings = configuration.GetSection("ConnectionStrings").Get<Dictionary<string, string>>(); _connection = connection; _connection.ConnectionString = connectionStrings.Where(s => s.Key.ToLower().Contains("read")).FirstOrDefault().Value; } /// <summary> /// 连接 /// </summary> public IDbConnection Connection { get { return _connection; } } /// <summary> /// Executes a single-row query, returning the data typed as type. /// </summary> /// <param name="type">The type to return.</param> /// <param name="sql">The SQL to execute for the query.</param> /// <param name="param">The parameters to pass, if any.</param> /// <param name="transaction">The transaction to use, if any.</param> /// <param name="buffered">Whether to buffer results in memory.</param> /// <param name="commandTimeout">The command timeout (in seconds).</param> /// <param name="commandType">The type of command to execute.</param> /// <returns>A sequence of data of the supplied type; if a basic type(int, string, etc) is queried then the data from the first column in assumed, otherwise an instance is created per row, and a direct column-name===member-name mapping is assumed(case insensitive). /// 异常:T:System.ArgumentNullException:type is null. /// </returns> public IEnumerable<object> Query(Type type, string sql, object param = null, IDbTransaction transaction = null, bool buffered = true, int? commandTimeout = null, CommandType? commandType = null) { return _connection.Query(type, sql, param, transaction, buffered, commandTimeout, commandType); } //这时省略n个方法 }
剩下的就是注入了,使用读时用IDapperPlusRead就可以,写就用IDapperPlusWrite。
public void ConfigureServices(IServiceCollection services) { services.AddControllers(); services.AddScoped<IDbConnection, MySqlConnection>(); services.AddScoped<IDapperPlusRead, DapperPlusRead>(); services.AddScoped<IDapperPlusWrite, DapperPlusWrite>(); }
appsettings.json
"ConnectionStrings": { "ReadConnectionString": "server=127.0.0.1;uid=root;pwd=root;database=read_mysql_testdb", "WriteConnectionString": "server=127.0.0.1;uid=root;pwd=root;database=write_mysql_testdb" }
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标签:transaction,data,读写,分离,query,Dapper,null,type,public 来源: https://www.cnblogs.com/ljknlb/p/15864269.html
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