> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/general-resources/database-theory/understanding-the-network-database-model.md).

# Understanding the Network Database Model

The network database model was a progression from the [hierarchical database model](/docs/general-resources/database-theory/understanding-the-hierarchical-database-model.md) and was designed to solve some of that model's problems, specifically the lack of flexibility. Instead of only allowing each child to have one parent, this model allows each child to have multiple parents (it calls the children *members* and the parents *owners*). It addresses the need to model more complex relationships such as the orders/parts many-to-many relationship mentioned in the [hierarchical article](/docs/general-resources/database-theory/understanding-the-hierarchical-database-model.md). As you can see in the figure below, *A1* has two members, *B1* and *B2*. *B1.* is the owner of *C1*, *C2*, *C3* and *C4*. However, in this model, *C4* has two owners, *B1* and *B2*.

```mermaid
flowchart TD
    accTitle: Network database model
    accDescr {
        A1 owns two members, B1 and B2. B1 owns C1, C2, C3 and C4, while B2 owns
        C4, C5 and C6, so C4 has two owners, B1 and B2. C3 owns D1, D2, D3 and D4,
        while C4 also owns D4, so D4 likewise has two owners, C3 and C4.
    }
    A1["A1"] --> B1["B1"]
    A1 --> B2["B2"]
    B1 --> C1["C1"]
    B1 --> C2["C2"]
    B1 --> C3["C3"]
    B1 --> C4["C4"]
    B2 --> C4
    B2 --> C5["C5"]
    B2 --> C6["C6"]
    C3 --> D1["D1"]
    C3 --> D2["D2"]
    C3 --> D3["D3"]
    C3 --> D4["D4"]
    C4 --> D4
    classDef n fill:#e2f0f2,stroke:#0a5a6b,stroke-width:2px,color:#111;
    class A1,B1,B2,C1,C2,C3,C4,C5,C6,D1,D2,D3,D4 n
```

*In the network model, a record such as C4 or D4 can have more than one owner.*

Of course, this model has its problems, or everyone would still be using it. It is more difficult to implement and maintain, and, although more flexible than the hierarchical model, it still has flexibility problems, Not all relations can be satisfied by assigning another owner, and the programmer still has to understand the data structure well in order to make the model efficient.

<sub>*This page is licensed: CC BY-SA / Gnu FDL*</sub>

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