/// <summary>
/// 条件筛选
/// </summary>
/// <param name="expression"></param>
/// <returns></returns>
public IQuery <T> Where(string predicate)
{
var vistor = new WhereExpressionVisitor <T>();
vistor.Evaluate(null, _builder, predicate);
return(this);
}
/// <summary>
/// 条件筛选
/// </summary>
/// <param name="expression"></param>
/// <returns></returns>
public IQuery <T> Where(Expression <Func <T, bool> > expression)
{
var vistor = new WhereExpressionVisitor <T>();
if (expression != null)
{
vistor.Evaluate(expression, _builder);
}
return(this);
}
/// <summary>
/// 批量删除
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="expression">删除条件</param>
/// <returns></returns>
public virtual int Delete <T>(Expression <Func <T, bool> > expression) where T : class
{
if (expression == null)
{
return(0);
}
var builder = new SqlBuilder <T>(Adapter, false);
var resolve = new WhereExpressionVisitor <T>();
resolve.Evaluate(expression, builder);
string sql = $"DELETE {builder.Table} FROM {builder.Table} {builder.Where}";
return(Connection.Execute(sql, builder.Parameters, Transaction));
}
/// <summary>
/// 批量修改
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="whereExpression">修改条件</param>
/// <param name="updateExpression">修改字段</param>
/// <returns></returns>
public virtual int Update <T>(Expression <Func <T, bool> > whereExpression, Expression <Func <T, T> > updateExpression)
where T : class
{
if (whereExpression == null)
{
return(0);
}
var builder = new SqlBuilder <T>(Adapter, false);
var resolve = new WhereExpressionVisitor <T>();
resolve.Evaluate(whereExpression, builder);
string set = string.Empty;
var expression = (MemberInitExpression)updateExpression.Body;
int i = 0;
int bindingCount = expression.Bindings.Count;
foreach (var binding in expression.Bindings)
{
i++;
var name = binding.Member.Name;
object value;
var memberExpression = ((MemberAssignment)binding).Expression;
var constantExpression = memberExpression as ConstantExpression;
if (constantExpression != null)
{
value = constantExpression.Value;
}
else
{
var lambda = Expression.Lambda(memberExpression, null);
value = lambda.Compile().DynamicInvoke();
}
var column = builder.Adapter.Field(builder.Table, builder.TableAliasName, name);
set += $"{column}=@{name}";
if (i < bindingCount)
{
set += ", ";
}
builder.Parameters.Add(name, value);
}
var table = $"{(builder.IsEnableAlias ? builder.TableAliasName : builder.Table)}";
string sql = $"UPDATE {table} SET {set} {builder.Where}";
return(Connection.Execute(sql, builder.Parameters, Transaction));
}