python网页制作实例_icons8官网_江东怎样优化seo_长沙疫情最新消息

1、获取表结构

//获取表结构,无分库
List<DbTableInfo> dbTableInfos =_freeSql.DbFirst.GetTablesByDatabase(_freeSql.DbFirst.GetDatabases()[0]);

2、序列化表结构，序列化时Table字段会循环引用，需要排除掉

//备份表结构
dbTableInfos.AsParallel().WithDegreeOfParallelism(_backupConfig.backupThread).ForAll(_ =>
{//目录名称就是表名string tempPath = Path.Combine(filePathName, _.Name);//文件string tempFilePath = Path.Combine(tempPath, _.Name);_iLogger.Info($"备份表:{_.Name},备份文件路径:{tempPath}");if (!Directory.Exists(tempPath)){Directory.CreateDirectory(tempPath);}//表结构string tableStructure = JsonHelperEx.SerializeSettingsEx(_, new Newtonsoft.Json.JsonSerializerSettings(){ContractResolver = new IgnorePropertiesContractResolver(new[] { "Table" })});//写入文件File.WriteAllText(tempFilePath, tableStructure);_iLogger.Info($"备份表结构:{_.Name},完成");
});

注：排除的代码

/// <summary>
/// 序列化时过滤某个字段
/// </summary>
public class IgnorePropertiesContractResolver : DefaultContractResolver
{private readonly HashSet<string> _ignoreProps;/// <summary>/// 构造/// </summary>/// <param name="propNamesToIgnore"></param>public IgnorePropertiesContractResolver(IEnumerable<string> propNamesToIgnore){_ignoreProps = new HashSet<string>(propNamesToIgnore);}/// <summary>/// 创建映射/// </summary>/// <param name="member"></param>/// <param name="memberSerialization"></param>/// <returns></returns>protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization){JsonProperty property = base.CreateProperty(member, memberSerialization);if (_ignoreProps.Contains(property.PropertyName)){property.ShouldSerialize = _ => false;}return property;}
}

3、备份数据

//数据
List<object> list = _freeSql.Select<object>().AsTable((_, _) => _.Name).Page(i, pageNum).ToList();
_iLogger.Info($"第 {i} 页数据:{list.Count}");
//处理数据
File.WriteAllText(tempDataFilePath, JsonConvert.SerializeObject(list, Formatting.Indented));

4、恢复表结构，将文件加载后反序列化恢复数据对象DbTableInfo

DbTableInfo dbTableInfo = JsonConvert.DeserializeObject<DbTableInfo>(json);

//处理注解
List<Attribute> attributes = new List<Attribute>();//表注解
attributes.Add(new TableAttribute() { Name = dbTableInfo.Name });
//索引注解
dbTableInfo.Uniques.ForEach(uni =>
{attributes.Add(new IndexAttribute(uni.Name, uni.Columns[0].Column.Name.ToLower(), uni.IsUnique));
});DynamicCompileBuilder dynamicCompile =_freeSql.CodeFirst.DynamicEntity(_.Name, attributes.ToArray());
//列映射
dbTableInfo.Columns.ForEach(col =>{_iLogger.Info($"备份到字段：{col.Name}");dynamicCompile = dynamicCompile.Property(col.Name, typeof(string), new ColumnAttribute{IsIdentity = col.IsIdentity,IsPrimary = col.IsPrimary,IsNullable = col.IsNullable,Position = (short)col.Position,StringLength = col.MaxLength});});//恢复结构
_freeSql.CodeFirst.SyncStructure(dynamicCompile.Build().Type);

5、恢复数据也是一样，读取文件，序列化插入表中