关系数据库元数据处理类(三) 创建查询元数据公共类

public abstract class BaseMetadata : IMetadata
    {
        protected IDbUtility DbUtility;

        protected BaseMetadata(IDbUtility dbUtility)
        {
            DbUtility = dbUtility;
        }

        #region 字符串

        /// <summary>
        /// 获取所有数据库信息的字符串
        /// </summary>
        /// <returns></returns>
        protected abstract string GetDataBaseSting();

        /// <summary>
        /// 获取所有表信息字符串
        /// </summary>
        /// <returns></returns>
        protected abstract string GetDataTableString(string database = "");

        /// <summary>
        /// 获取所有字段字符串
        /// </summary>
        /// <returns></returns>
        protected abstract string GetDataColumnString();

        /// <summary>
        /// 获取所有外键字符串
        /// </summary>
        /// <returns></returns>
        protected abstract string GetDataRelationString();

        #endregion

        #region 转换

        /// <summary>
        /// 将DataRow转换为Database对象
        /// </summary>
        /// <param name="table"></param>
        /// <returns></returns>
        protected abstract List<Database> ConversionDatabase(DataTable table);

        /// <summary>
        /// 将DataRow转换为Table对象
        /// </summary>
        /// <param name="table"></param>
        /// <returns></returns>
        protected abstract List<Table> ConversionDataTable(DataTable table);

        /// <summary>
        /// 将DataRow转换为Table对象
        /// </summary>
        /// <param name="table"></param>
        /// <returns></returns>
        protected abstract List<Column> ConversionColumn(DataTable table);

        /// <summary>
        /// 将DataRow转换为Table对象
        /// </summary>
        /// <param name="table"></param>
        /// <returns></returns>
        protected abstract List<Relation> ConversionDataRelation(DataTable table);

        #endregion

        #region 操作

        public Database GetDatabase(ISpecification<Database> specification)
        {
            return GetAllDatabase().First(specification.SatisfiedBy().Compile());
        }

        public List<Database> GetAllDatabase()
        {
            return FinDatabases(null);
        }

        public List<Database> FinDatabases(ISpecification<Database> specification)
        {
            DataTable data = DbUtility.ExecuteDataTable(GetDataBaseSting());
            List<Database> databases = ConversionDatabase(data);
            if (specification != null)
                databases = databases.Where(specification.SatisfiedBy().Compile()).ToList();
            return databases;
        }

        public Table GeTable(ISpecification<Table> specification)
        {
            return GetAllTable().First(specification.SatisfiedBy().Compile());
        }

        public List<Table> GetAllTable()
        {
            return FindTables(null);
        }

        public List<Table> FindTables(ISpecification<Table> specification)
        {
            DataTable data = DbUtility.ExecuteDataTable(GetDataTableString());
            List<Table> tables = ConversionDataTable(data);
            if (specification != null)
                tables = tables.Where(specification.SatisfiedBy().Compile()).ToList();
            return tables;
        }

        public Column GetColumn(ISpecification<Column> specification)
        {
            return GetAllColumns().First(specification.SatisfiedBy().Compile());
        }

        public List<Column> GetAllColumns()
        {
            return FindColumns(null);
        }

        public List<Column> FindColumns(ISpecification<Column> specification)
        {
            DataTable data = DbUtility.ExecuteDataTable(GetDataColumnString());
            List<Column> columns = ConversionColumn(data);
            if (specification != null)
                columns = columns.Where(specification.SatisfiedBy().Compile()).ToList();
            return columns;
        }

        public List<Relation> GetAllRelation()
        {
            return FindRelations(null);
        }

        public Relation GeRelation(ISpecification<Relation> specification)
        {
            return GetAllRelation().First(specification.SatisfiedBy().Compile());
        }


        public List<Relation> FindRelations(ISpecification<Relation> specification)
        {
            DataTable data = DbUtility.ExecuteDataTable(GetDataRelationString());
            List<Relation> relations = ConversionDataRelation(data);
            if (specification != null)
                relations = relations.Where(specification.SatisfiedBy().Compile()).ToList();
            return relations;
        }

        #endregion
    }