Elixir “exto.Schema.Metadata”的用途是什么？（即“元”字段）
我计划使用Elixir “exto.Schema.Metadata”的用途是什么？（即“元”字段）,elixir,schema,ecto,Elixir,Schema,Ecto,我计划使用exto的Schema和Changeset仅用于验证，而不将任何内容持久化到数据库中，并试图弄清楚是否应该使用。根据文档，它们之间的唯一区别是“嵌入式模式不需要源名称，也不包含元数据字段。” 因此，我选择了嵌入式_schema/1，工作非常出色，但它让我想知道元数据的确切用途是什么？对于澄清这一点没有多大帮助： 存储结构的元数据 这些字段是： 状态-结构生命周期中的状态，其中一个为：build，：loaded， ：删除 source—查询旁边的架构的源 前缀，默认为{nil，“sou
extoSchemaChangeset嵌入式_schema/1- 状态-结构生命周期中的状态，其中一个为：build，：loaded， ：删除
- source—查询旁边的架构的源 前缀，默认为{nil，“source”}
- context-由 数据库
嵌入式_模式/1更新 忘记了即将推出的Exto 3和Hexdocs文档仍然适用于Exto 2.2.11。在源代码中找到，但更详细：
Stores metadata of a struct.
## State
The state of the schema is stored in the `:state`
field and allows following values:
* `:built` - the struct was constructed in
memory and is not persisted
to database yet;
* `:loaded` - the struct was loaded from database
and represents persisted data;
* `:deleted` - the struct was deleted and no longer
represents persisted data.
## Source
The `:source` tracks the (table or collection) where
the struct is or should be persisted to.
## Prefix
Tracks the source prefix in the data storage.
## Context
The `:context` field represents additional state some
databases require for proper updates of data. It is
not used by the built-in adapters of `Ecto.Adapters.Postres`
and `Ecto.Adapters.MySQL`.
## Schema
The `:schema` field refers the module name for the
schema this metadata belongs to.
An Ecto schema is used to map any data source into an Elixir struct.
The definition of the schema is possible through two main APIs:
`schema/2` and `embedded_schema/1`.
`schema/2` is typically used to map data from a persisted source,
usually a database table, into Elixir structs and vice-versa. For
this reason, the first argument of `schema/2` is the source (table)
name. Structs defined with `schema/2` also contain a `__meta__` field
with metadata holding the status of the struct, for example, if it
has been built, loaded or deleted.
On the other hand, `embedded_schema/1` is used for defining schemas
that are embedded in other schemas or only exist in-memory. For example,
you can use such schemas to receive data from a command line interface
and validate it, without ever persisting it elsewhere. Such structs
do not contain a `__meta__` field, as they are never persisted.
)EXTO内部使用
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-结构生命周期中的状态，其中一个是状态
，：builded
，：加载的：删除的
-查询前缀旁边架构的源， 默认值为source{nil，“source”}
-数据库存储的上下文上下文
exto.Schema.Metadataschemaembedded_schema旁注：我的一般建议是，当你想简单地理解一些东西时，不要阅读文档