在 sqlite 中实现层次结构

Question

我是 SQL 的初学者，我正在使用 SQLite 编写 C# 应用程序。我需要帮助在我的数据库中实现https://imgur.com/a/NImUPCc 中显示的层次结构。我知道对于私人帐户，它将是名为 PrivateAccounts 的表（应该将其称为 PersonalAccounts 不是私人的，但现在没那么重要），在那里我会抛出许多带有 ID、登录名等的行。但是怎么做它与公司帐户，哪里有公司的一般帐户，我需要将在该公司工作的人的帐户链接到该帐户？为每家公司创建表是否有效？但这会在数据库中造成很大的混乱，因为如果可能的话，我希望为公司帐户和个人帐户提供一个数据库

Answer 1

我建议 3 张桌子。

一个实体表，其中包含帐户所有者的详细信息（并使用对拥有实体的引用来满足子公司的需求），并具有用于类型（私人或公司）的列。

具有帐户名称和所有者的帐户表。

用于记录交易的Account Transaction表，基本上是两列，一列引用账户（因此实体）和交易金额。

以上内容非常简单，您可能希望添加更多列。

示例

以下是一个简短的演示，最终以帐户名称、直接所有者名称和显示的帐户类型显示帐户余额。

DROP TABLE IF EXISTS entity;
DROP TABLE IF EXISTS account;
DROP TABLE IF EXISTS account_transaction;
CREATE TABLE IF NOT EXISTS entity (id INTEGER PRIMARY KEY, entity_name TEXT, entity_type INTEGER, entity_owning_entity);
CREATE TABLE IF NOT EXISTS account (id INTEGER PRIMARY KEY, account_name TEXT, entity_reference INTEGER);
CREATE TABLE IF NOT EXISTS account_transaction (id INTEGER PRIMARY KEY, account_reference INTEGER, amount REAL);
INSERT INTO entity (entity_name, entity_type, entity_owning_entity)
    VALUES
        ("Company 1",1,null), -- will be id 1 
        ("Company 2",1, null), -- will be id 2
      ("Sub Company A",1,1), -- Owned by Company 1 will be id 3
        ("Sub Company B",1,1), -- Owned by Company 1 will be id 4
        ("Sub Company X",1,2), -- Owned by Company 2 will be id 5
        ("Sub Company Y",1,2), -- Owned by Company 2 will be id 6
        ("Fred",0,null), -- Not owned personal type (0) will be id 7
        ("Mary",0,null) -- Not owned, personal type, will be id 8
;
INSERT INTO account (account_name, entity_reference)
    VALUES
        ("Fred's Cheque",7), -- id 1
        ("Sub A Cheque",3), -- id 2
        ("Fred's Savings",7), -- id 3
        ("Mary's Cheque",8), -- id 4
      ("Sub X Chequ",5) -- id 5
;

INSERT INTO account_transaction (account_reference, amount)
    VALUES
        (3,123.45),(3,57.55),(3,200), -- 381 for Fred's Cheque (i.e. references id 3 in the account table)
        (2,100),(2,100),(2,100),(2,100), -- 400 for Sub A Cheque (i.e. references id 2)
        (1,10),
        (4,15),(4,15),(4,30),
        (5,13),(5,14),(5,15),(5,16),(5,17)
;

WITH cte1(id,name) AS 
  -- Use Common Table Expression (temp table) to resolve owner of an entity
    (SELECT id, (SELECT entity_name FROM entity WHERE me.entity_owning_entity = id) FROM entity AS me)

-- Main SELECT Query
SELECT
  -- Handle case when no entity owner or when entity owner
  CASE
        WHEN (SELECT name FROM cte1 where cte1.id = entity.id) IS NULL 
            THEN entity_name
            ELSE (SELECT name FROM cte1 where cte1.id = entity.id)||'-'||entity_name
    END AS AccountOwner,
    account_name AS Account, -- Show the axccount_name
    sum(amount) AS Balance,  -- Show the balance
    -- Use and appropriate value for the type (private or company account)
    CASE
            WHEN entity_type = 1 THEN 'Company'
            WHEN entity_type = 0 THEN 'Private'
        END AS Type
FROM account_transaction -- main table
    JOIN account ON account.id = account_reference -- relationship to the account table
    JOIN entity ON entity.id = entity_reference -- relationship to the entity table
GROUP BY account.id -- group according to accounts (i.e. 1 row is made from all rows in a group for aggregates such a sum)
ORDER BY AccountOwner -- Order result according to the Account Owner 
;

结果

SELECT 查询将返回：-

• 请注意，您通常不会假设 id 是特定值，为了简洁起见，使用了它们的假设。