Python 迴圈語句以及常用方法案例
轉載自https://www.cnblogs.com/gskstudy/p/13306399.html
對於EFCore 3.1
using System.Linq; using System.Reflection; using System.Collections.Generic; using Microsoft.EntityFrameworkCore.Query.SqlExpressions; using Microsoft.EntityFrameworkCore.Query;
public static string ToSql
var sqlGenerator = factory.Create();
var command = sqlGenerator.GetCommand(selectExpression);
string sql = command.CommandText;
return sql;
}
private static object Private(this object obj, string privateField) ⇒ obj?.GetType().GetField(privateField, BindingFlags.Instance | BindingFlags.NonPublic)?.GetValue(obj);
private static T Private
對於EFCore 3.0
public static string ToSql
對於EFCore 2.1.2
static class IQueryableToSql { private static readonly TypeInfo QueryCompilerTypeInfo = typeof(QueryCompiler).GetTypeInfo(); private static readonly FieldInfo QueryCompilerField = typeof(EntityQueryProvider).GetTypeInfo().DeclaredFields.First(x ⇒ x.Name == "_queryCompiler"); private static readonly FieldInfo QueryModelGeneratorField = QueryCompilerTypeInfo.DeclaredFields.First(x ⇒ x.Name == "_queryModelGenerator"); private static readonly FieldInfo queryContextFactoryField = QueryCompilerTypeInfo.DeclaredFields.First(x ⇒ x.Name == "_queryContextFactory"); private static readonly FieldInfo loggerField = QueryCompilerTypeInfo.DeclaredFields.First(x ⇒ x.Name == "_logger"); private static readonly FieldInfo DataBaseField = QueryCompilerTypeInfo.DeclaredFields.Single(x ⇒ x.Name == "_database"); private static readonly PropertyInfo DatabaseDependenciesField = typeof(Database).GetTypeInfo().DeclaredProperties.Single(x ⇒ x.Name == "Dependencies");
public static (string sql, IReadOnlyDictionary<string, object> parameters) ToSql<TEntity>(IQueryable<TEntity> query) where TEntity : class
{
var queryCompiler = (QueryCompiler)QueryCompilerField.GetValue(query.Provider);
var queryContextFactory = (IQueryContextFactory)queryContextFactoryField.GetValue(queryCompiler);
var logger = (Microsoft.EntityFrameworkCore.Diagnostics.IDiagnosticsLogger<DbLoggerCategory.Query>)loggerField.GetValue(queryCompiler);
var queryContext = queryContextFactory.Create();
var modelGenerator = (QueryModelGenerator)QueryModelGeneratorField.GetValue(queryCompiler);
var newQueryExpression = modelGenerator.ExtractParameters(logger, query.Expression, queryContext);
var queryModel = modelGenerator.ParseQuery(newQueryExpression);
var database = (IDatabase)DataBaseField.GetValue(queryCompiler);
var databaseDependencies = (DatabaseDependencies)DatabaseDependenciesField.GetValue(database);
var queryCompilationContext = databaseDependencies.QueryCompilationContextFactory.Create(false);
var modelVisitor = (RelationalQueryModelVisitor)queryCompilationContext.CreateQueryModelVisitor();
modelVisitor.CreateQueryExecutor<TEntity>(queryModel);
var command = modelVisitor.Queries.First().CreateDefaultQuerySqlGenerator()
.GenerateSql(queryContext.ParameterValues);
return (command.CommandText, queryContext.ParameterValues);
}
}