/// <summary>
/// 根据类型<see cref="DbJoinKeyPairExpression"/>表达式创建表达式语句片段。
/// </summary>
/// <param name="context">生成上下文。</param>
/// <param name="expression">所在数据源。</param>
/// <param name="source">检索表达式。</param>
/// <returns>创建结果。</returns>
protected virtual IExpressionFragment CreateExpressionForJoinKeyPair(GenerateContext context, DbExpression expression, ISourceFragment source)
{
var content = (DbJoinKeyPairExpression)expression;
return(new BinaryFragment(context, EBinaryKind.Equal)
{
Left = source.CreateExpression(content.Left),
Right = source.CreateExpression(content.Right),
});
}
/// <inheritdoc/>
protected override IExpressionFragment CreateExpressionForBinary(GenerateContext context, DbExpression expression, ISourceFragment source)
{
var binary = (DbBinaryExpression)expression;
if (binary.Kind == EBinaryKind.Add && binary.ClrType == typeof(string))
{
return(new StringConcatFragment(context,
source.CreateExpression(binary.Left),
source.CreateExpression(binary.Right)));
}
return(base.CreateExpressionForBinary(context, expression, source));
}
/// <inheritdoc/>
protected override IExpressionFragment CreateExpressionForBinary(GenerateContext context, DbExpression expression, ISourceFragment source)
{
var binary = (DbBinaryExpression)expression;
if (binary.Kind == EBinaryKind.Add && binary.ClrType == typeof(string))
{
var scalar = new ScalarFragment(context,
source.CreateExpression(binary.Left),
source.CreateExpression(binary.Right));
scalar.Function = SupportMembers.String.Concat;
return(scalar);
}
return(base.CreateExpressionForBinary(context, expression, source));
}
/// <summary>
/// 根据类型<see cref="DbBinaryExpression"/>表达式创建表达式语句片段。
/// </summary>
/// <param name="context">生成上下文。</param>
/// <param name="expression">所在数据源。</param>
/// <param name="source">检索表达式。</param>
/// <returns>创建结果。</returns>
protected virtual IExpressionFragment CreateExpressionForBinary(GenerateContext context, DbExpression expression, ISourceFragment source)
{
var binary = (DbBinaryExpression)expression;
if (binary.Kind == EBinaryKind.AndAlso || binary.Kind == EBinaryKind.OrElse)
{
return(source.CreateExpression(binary.Left).Merge(binary.Kind, source.CreateExpression(binary.Right)));
}
else
{
return(new BinaryFragment(context, binary.Kind)
{
Left = source.CreateExpression(binary.Left),
Right = source.CreateExpression(binary.Right)
});
}
}
/// <summary>
/// 根据类型<see cref="DbUnaryExpression"/>表达式创建表达式语句片段。
/// </summary>
/// <param name="context">生成上下文。</param>
/// <param name="expression">所在数据源。</param>
/// <param name="source">检索表达式。</param>
/// <returns>创建结果。</returns>
protected virtual IExpressionFragment CreateExpressionForUnary(GenerateContext context, DbExpression expression, ISourceFragment source)
{
var unary = (DbUnaryExpression)expression;
return(new UnaryFragment(context, unary.Kind, unary.Type)
{
Expresssion = source.CreateExpression(unary.Expression)
});
}
/// <summary>
/// 根据类型<see cref="DbScalarFunctionExpression"/>表达式创建表达式语句片段。
/// </summary>
/// <param name="context">生成上下文。</param>
/// <param name="expression">所在数据源。</param>
/// <param name="source">检索表达式。</param>
/// <returns>创建结果。</returns>
protected virtual IExpressionFragment CreateExpressionForScalarFunction(GenerateContext context, DbExpression expression, ISourceFragment source)
{
var scalar = (DbScalarFunctionExpression)expression;
var result = new ScalarFragment(context)
{
Function = scalar.Function
};
foreach (var arg in scalar.Arguments)
{
result.Arguments.Add(source.CreateExpression(arg));
}
return(result);
}
