Fizz

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原文：https://gobuffalo.io/documentation/database/fizz/

Fizz

Fizz is a common DSL for migrating databases. It tries to be as database-agnostic as possible. This is the default language used by Pop to define database migrations.

Fizz 是一种用于迁移数据库的通用 DSL。它尝试尽可能地与数据库无关。这是 Pop 用于定义数据库迁移的默认语言。

Create a Table 创建表

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create_table("users") {
  t.Column("email", "string", {})
  t.Column("twitter_handle", "string", {"size": 50})
  t.Column("age", "integer", {"default": 0})
  t.Column("admin", "bool", {"default": false})
  t.Column("company_id", "uuid", {"default_raw": "uuid_generate_v1()"})
  t.Column("bio", "text", {"null": true})
  t.Column("joined_at", "timestamp", {})
}

create_table("todos") {
  t.Column("user_id", "integer", {})
  t.Column("title", "string", {"size": 100})
  t.Column("details", "text", {"null": true})
  t.ForeignKey("user_id", {"users": ["id"]}, {"on_delete": "cascade"})
}

The id column doesn’t have to be an integer. For instance, you can use an UUID type instead:

id 列不必是整数。例如，您可以使用 UUID 类型：

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create_table("users") {
  t.Column("id", "uuid", {primary: true})
  // ...
}

By default, fizz will generate two timestamp columns: created_at and updated_at.

默认情况下，fizz 将生成两列 timestamp ： created_at 和 updated_at 。

The t.Column method takes the following arguments: name of the column, the type of the field, and finally the last argument is any options you want to set on that column.

方法采用以下参数：列的名称、字段的类型，最后，最后一个参数是您想要在该列上设置的任何选项。

“Common” Types: “通用”类型：

string
text
timestamp, time, datetime
integer
bool
uuid

Any other type passed will be passed straight through to the underlying database.

传递的任何其他类型都将直接传递到基础数据库。

For example for PostgreSQL you could pass jsonb and it will be supported, however, SQLite will yell very loudly at you if you do the same thing!

例如，对于 PostgreSQL，您可以传递 jsonb ，它将得到支持，但是，如果您对 SQLite 执行相同的操作，它会非常大声地向您发出警告！

Supported Options: 支持的选项：

Option 选项	Description 说明	Example 示例
`primary`	Whether the column is the primary key. To have a composite key look below 列是否是主键。要查看复合键，请在下面查找	`{"primary": true}`
`size`	The size of the column. The default value for a string column is 255 (or 191 for MariaDB) 列的大小。字符串列的默认值为 255（或 MariaDB 的 191）	`{"size": 50}`
`scale`, `precision`	The scale and the precision for a float column 浮点列的比例和精度	`{"scale": 4, "precision": 2}`
`null`	By default columns are not allowed to be `null` 默认情况下，不允许列为 `null`	`{"null": true}`
`default`	The default value you want for this column. By default this is `null` 您希望为此列设置的默认值。默认情况下，这是 `null`	`{"default": 0}` `{"default": false}` `{"default": "foo"}`
`default_raw`	The default value defined as a database function 定义为数据库函数的默认值	`{"default_raw": "uuid_generate_v1()"}`
`after`	(MySQL Only) Add a column after another column in the table (仅限 MySQL) 在表中另一个列之后添加列	`{"after": "created_at"}`
`first`	(MySQL Only) Add a column to the first position in the table (仅限 MySQL) 将列添加到表中的第一个位置	`{"first": true}`

Disable Auto Timestamps 禁用自动时间戳

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create_table("users") {
  t.Column("id", "uuid", {primary: true})
  // ...
  // Disable auto-creation of created_at and updated_at columns
  t.DisableTimestamps()
}

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create_table("users", {timestamps: false}) {
  t.Column("id", "uuid", {primary: true})
  // ...
}

Drop a Table 删除表

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drop_table("table_name")

Rename a Table 重命名表

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rename_table("old_table_name", "new_table_name")

Add a Column 添加列

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add_column("table_name", "column_name", "string", {})

See above for more details on column types and options.

请参阅上文以了解有关列类型和选项的更多详细信息。

Alter a column 更改列

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change_column("table_name", "column_name", "string", {})

Rename a Column 重命名列

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rename_column("table_name", "old_column_name", "new_column_name")

Drop a Column 删除列

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drop_column("table_name", "column_name")

Composite Primary Keys 复合主键

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t.PrimaryKey("column_1", "column_2")

Please note that the t.PrimaryKey statement MUST be after the columns definitions.

请注意， t.PrimaryKey 语句必须在列定义之后。

Add an Index 添加索引

Supported Options: 支持的选项：

name - This defaults to table_name_column_name_idx name - 默认为 table_name_column_name_idx
unique

Simple Index: 简单索引：

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add_index("table_name", "column_name", {})

Multi-Column Index: 多列索引：

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add_index("table_name", ["column_1", "column_2"], {})

Unique Index: 唯一索引：

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add_index("table_name", "column_name", {"unique": true})

Index Names: 索引名称：

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add_index("table_name", "column_name", {}) # name => table_name_column_name_idx
add_index("table_name", "column_name", {"name": "custom_index_name"})

Rename an Index 重命名索引

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rename_index("table_name", "old_index_name", "new_index_name")

Drop an Index 删除索引

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drop_index("table_name", "index_name")

Add a Foreign Key 添加外键

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add_foreign_key("table_name", "field", {"ref_table_name": ["ref_column"]}, {
    "name": "optional_fk_name",
    "on_delete": "action",
    "on_update": "action",
})

Supported Options 支持的选项

name - This defaults to table_name_ref_table_name_ref_column_name_fk name - 默认为 table_name_ref_table_name_ref_column_name_fk
on_delete - CASCADE, SET NULL, …
on_update

Note: on_update and on_delete are not supported on CockroachDB yet. 注意：CockroachDB 尚不支持 on_update 和 on_delete 。

Drop a Foreign Key 删除外键

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drop_foreign_key("table_name", "fk_name", {"if_exists": true})

Supported Options 支持的选项

if_exists - Adds IF EXISTS condition if_exists - 添加 IF EXISTS 条件

Raw SQL 原始 SQL

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sql("select * from users;")

Execute an External Command 执行外部命令

Sometimes during a migration you need to shell out to an external command.

有时在迁移期间，您需要使用外部命令进行 shell 操作。

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exec("echo hello")

最后修改 October 10, 2024: 更新 (a4b8f85)