级联删除、递归删除，基于导航属性代码实现

[2881099]

以下代码，基于 OneToOne/OneToMany/ManyToMany 进行递归查询并删除，讨论待测试

public static string ToSqlCascade<T>(this IDelete<T> that)
{
    var delete = that as DeleteProvider;
    if (delete == null) return null;
    if (delete._whereTimes <= 0 || delete._where.Length == 0) return null;
    if (LocalGetNavigates(delete._table).Any() == false) return that.ToSql();

    var fsql = delete._orm;
    var sb = new StringBuilder();
    Dictionary<string, bool> eachdic = new Dictionary<string, bool>();

    var rootSel = fsql.Select<object>().AsType(delete._table.Type).Where(delete._where.ToString());
    var rootItems = rootSel.ToList();
    LocalEach(delete._table.Type, rootItems, true);
    return sb.ToString();

    List<NativeTuple<TableRef, PropertyInfo>> LocalGetNavigates(TableInfo tb)
    {
        return tb.Properties.Where(a => tb.ColumnsByCs.ContainsKey(a.Key) == false)
            .Select(a => new NativeTuple<TableRef, PropertyInfo>(tb.GetTableRef(a.Key, false), a.Value))
            .Where(a => a.Item1 != null && a.Item1.RefType != TableRefType.ManyToOne)
            .ToList();
    }
    void LocalEach(Type itemType, List<object> items, bool isOneToOne)
    {
        items = items?.Where(item =>
        {
            var itemKeystr = FreeSql.Extensions.EntityUtil.EntityUtilExtensions.GetEntityKeyString(fsql, itemType, item, false);
            var eachdicKey = $"{itemType.FullName},{itemKeystr}";
            if (eachdic.ContainsKey(eachdicKey)) return false;
            eachdic.Add(eachdicKey, true);
            return true;
        }).ToList();
        if (items?.Any() != true) return;

        var tb = fsql.CodeFirst.GetTableByEntity(itemType);
        var navs = LocalGetNavigates(tb);

        var otos = navs.Where(a => a.Item1.RefType == TableRefType.OneToOne).ToList();
        if (otos.Any())
        {
            foreach (var oto in otos)
            {
                var childsSel = fsql.Select<object>().AsType(oto.Item1.RefEntityType) as Select1Provider<object>;
                var refitems = items.Select(item =>
                {
                    var refitem = oto.Item1.RefEntityType.CreateInstanceGetDefaultValue();
                    for (var a = 0; a < oto.Item1.Columns.Count; a++)
                    {
                        var colval = FreeSql.Extensions.EntityUtil.EntityUtilExtensions.GetPropertyValue(tb, item, oto.Item1.Columns[a].CsName);
                        FreeSql.Extensions.EntityUtil.EntityUtilExtensions.SetPropertyValue(childsSel._tables[0].Table, refitem, oto.Item1.RefColumns[a].CsName, colval);
                    }
                    return refitem;
                }).ToList();

                childsSel.Where(childsSel._commonUtils.WhereItems(oto.Item1.RefColumns.ToArray(), "a.", refitems));
                var childs = childsSel.ToList();
                LocalEach(oto.Item1.RefEntityType, childs, false);
            }
        }

        var otms = navs.Where(a => a.Item1.RefType == TableRefType.OneToMany).ToList();
        if (otms.Any())
        {
            foreach (var otm in otms)
            {
                var childsSel = fsql.Select<object>().AsType(otm.Item1.RefEntityType) as Select1Provider<object>;
                var refitems = items.Select(item =>
                {
                    var refitem = otm.Item1.RefEntityType.CreateInstanceGetDefaultValue();
                    for (var a = 0; a < otm.Item1.Columns.Count; a++)
                    {
                        var colval = FreeSql.Extensions.EntityUtil.EntityUtilExtensions.GetPropertyValue(tb, item, otm.Item1.Columns[a].CsName);
                        FreeSql.Extensions.EntityUtil.EntityUtilExtensions.SetPropertyValue(childsSel._tables[0].Table, refitem, otm.Item1.RefColumns[a].CsName, colval);
                    }
                    return refitem;
                }).ToList();

                childsSel.Where(childsSel._commonUtils.WhereItems(otm.Item1.RefColumns.ToArray(), "a.", refitems));
                var childs = childsSel.ToList();
                LocalEach(otm.Item1.RefEntityType, childs, true);
            }
        }

        var mtms = navs.Where(a => a.Item1.RefType == TableRefType.ManyToMany).ToList();
        if (mtms.Any())
        {
            foreach (var mtm in mtms)
            {
                var childsSel = fsql.Select<object>().AsType(mtm.Item1.RefMiddleEntityType) as Select1Provider<object>;
                var miditems = items.Select(item =>
                {
                    var refitem = mtm.Item1.RefMiddleEntityType.CreateInstanceGetDefaultValue();
                    for (var a = 0; a < mtm.Item1.Columns.Count; a++)
                    {
                        var colval = FreeSql.Extensions.EntityUtil.EntityUtilExtensions.GetPropertyValue(tb, item, mtm.Item1.Columns[a].CsName);
                        FreeSql.Extensions.EntityUtil.EntityUtilExtensions.SetPropertyValue(childsSel._tables[0].Table, refitem, mtm.Item1.MiddleColumns[a].CsName, colval);
                    }
                    return refitem;
                }).ToList();

                childsSel.Where(childsSel._commonUtils.WhereItems(mtm.Item1.MiddleColumns.Take(mtm.Item1.Columns.Count).ToArray(), "a.", miditems));
                var childs = childsSel.ToList();
                LocalEach(mtm.Item1.RefEntityType, childs, true);
            }
        }

        var delSql = fsql.Delete<object>().AsType(itemType).WhereDynamic(items).ToSql();
        if (string.IsNullOrWhiteSpace(delSql)) throw new Exception($"ToSqlCascade 失败");
        if (sb.Length > 0) sb.Append("\r\n\r\n;\r\n\r\n");
        sb.Append(delSql);
    }
}