private static AbstractSqlCondition ParseBinaryExpression(AbstractSqlCommandWithWhere sourceCommand, BinaryExpression expr)
{
switch (expr.NodeType)
{
case ExpressionType.Equal:
return(ParseBinaryExpression(sourceCommand, expr, SqlOperator.Equal));
case ExpressionType.NotEqual:
return(ParseBinaryExpression(sourceCommand, expr, SqlOperator.NotEqual));
case ExpressionType.GreaterThan:
return(ParseBinaryExpression(sourceCommand, expr, SqlOperator.GreaterThan));
case ExpressionType.LessThan:
return(ParseBinaryExpression(sourceCommand, expr, SqlOperator.LessThan));
case ExpressionType.GreaterThanOrEqual:
return(ParseBinaryExpression(sourceCommand, expr, SqlOperator.GreaterThanOrEqual));
case ExpressionType.LessThanOrEqual:
return(ParseBinaryExpression(sourceCommand, expr, SqlOperator.LessThanOrEqual));
case ExpressionType.And:
case ExpressionType.AndAlso:
return(SqlLinqCondition.ParseCondition(sourceCommand, expr.Left) & SqlLinqCondition.ParseCondition(sourceCommand, expr.Right));
case ExpressionType.Or:
case ExpressionType.OrElse:
return(SqlLinqCondition.ParseCondition(sourceCommand, expr.Left) | SqlLinqCondition.ParseCondition(sourceCommand, expr.Right));
default:
throw new LinqNotSupportedException("Not supported this linq operation!");
}
}
/// <summary>
/// 设置指定查询的语句并返回当前语句
/// </summary>
/// <typeparam name="T">实体类类型</typeparam>
/// <param name="cmd">更新语句</param>
/// <param name="expr">Linq表达式</param>
/// <exception cref="LinqNotSupportedException">Linq操作不支持</exception>
/// <returns>当前语句</returns>
/// <example>
/// <code lang="C#">
/// <![CDATA[
/// public class UserRepository : DatabaseTable<User>
/// {
/// //other necessary code
///
/// public Boolean UpdateEntity(User user)
/// {
/// return this.Update()
/// .Set<User>(c => c.UserName, user.UserName)
/// .Where<User>(c => c.UserID == user.UserID)
/// .Result() > 0;
///
/// //UPDATE tbl_Users SET UserName = @UserName WHERE UserID = @UserID
/// //@UserName = user.UserName
/// //@UserID = user.UserID
/// }
/// }
/// ]]>
/// </code>
/// </example>
public static UpdateCommand Where <T>(this UpdateCommand cmd, Expression <Func <T, Boolean> > expr)
{
return(cmd.Where(SqlLinqCondition.Create <T>(cmd, expr)));
}
/// <summary>
/// 设置指定查询的语句并返回当前语句
/// </summary>
/// <typeparam name="T">实体类类型</typeparam>
/// <param name="cmd">选择语句</param>
/// <param name="expr">Linq表达式</param>
/// <exception cref="LinqNotSupportedException">Linq操作不支持</exception>
/// <returns>当前语句</returns>
public static SelectCommand Having <T>(this SelectCommand cmd, Expression <Func <T, Boolean> > expr)
{
return(cmd.Having(SqlLinqCondition.Create <T>(cmd, expr)));
}
/// <summary>
/// 创建新的Sql条件语句
/// </summary>
/// <typeparam name="T">实体类类型</typeparam>
/// <param name="sourceCommand">来源语句</param>
/// <param name="expr">Linq表达式</param>
/// <exception cref="LinqNotSupportedException">Linq操作不支持</exception>
/// <exception cref="NullAttributeException">没有设置特性</exception>
/// <returns>Sql条件语句</returns>
public static AbstractSqlCondition Create <T>(AbstractSqlCommandWithWhere sourceCommand, Expression <Func <T, Boolean> > expr)
{
return(SqlLinqCondition.ParseCondition(sourceCommand, expr.Body));
}