internal static SelectExpression WhereAndSelectDatabaseExpressions(AdventureWorks adventureWorks)
{
QueryCompilationContext compilationContext = adventureWorks.GetService <IQueryCompilationContextFactory>()
.Create(async: false);
SelectExpression databaseExpression = new SelectExpression(
dependencies: new SelectExpressionDependencies(adventureWorks.GetService <IQuerySqlGeneratorFactory>(), adventureWorks.GetService <IRelationalTypeMappingSource>()),
queryCompilationContext: (RelationalQueryCompilationContext)compilationContext);
MainFromClause querySource = new MainFromClause(
itemName: "product",
itemType: typeof(Product),
fromExpression: Expression.Constant(adventureWorks.ProductCategories));
TableExpression tableExpression = new TableExpression(
table: nameof(Product),
schema: AdventureWorks.Production,
alias: querySource.ItemName,
querySource: querySource);
databaseExpression.AddTable(tableExpression);
IEntityType productEntityType = adventureWorks.Model.FindEntityType(typeof(Product));
IProperty nameProperty = productEntityType.FindProperty(nameof(Product.Name));
ColumnExpression nameColumn = new ColumnExpression(
name: nameof(Product.Name), property: nameProperty, tableExpression: tableExpression);
databaseExpression.AddToProjection(nameColumn);
databaseExpression.AddToPredicate(Expression.GreaterThan(
left: new ExplicitCastExpression(
operand: new SqlFunctionExpression(
functionName: "LEN",
returnType: typeof(int),
arguments: new Expression[] { nameColumn }),
type: typeof(int)),
right: Expression.Constant(10)));
return(databaseExpression.WriteLine());
}
internal static SelectExpression SelectAndFirstDatabaseExpressions(AdventureWorks adventureWorks)
{
QueryCompilationContext compilationContext = adventureWorks.GetService <IQueryCompilationContextFactory>()
.Create(async: false);
SelectExpression selectExpression = new SelectExpression(
dependencies: new SelectExpressionDependencies(adventureWorks.GetService <IQuerySqlGeneratorFactory>(), adventureWorks.GetService <IRelationalTypeMappingSource>()),
queryCompilationContext: (RelationalQueryCompilationContext)compilationContext);
MainFromClause querySource = new MainFromClause(
itemName: "product",
itemType: typeof(Product),
fromExpression: Expression.Constant(adventureWorks.ProductCategories));
TableExpression tableExpression = new TableExpression(
table: nameof(Product),
schema: AdventureWorks.Production,
alias: querySource.ItemName,
querySource: querySource);
selectExpression.AddTable(tableExpression);
IEntityType productEntityType = adventureWorks.Model.FindEntityType(typeof(Product));
IProperty nameProperty = productEntityType.FindProperty(nameof(Product.Name));
selectExpression.AddToProjection(new ColumnExpression(
name: nameof(Product.Name), property: nameProperty, tableExpression: tableExpression));
selectExpression.Limit = Expression.Constant(1);
return(selectExpression.WriteLine());
}
