Question

如果我执行MyClass.columns，则列将具有type属性，其值如：integer，：string，：datetime等。如何获取该类型并将其映射到ruby类型？

例如：

：integer =>整数

：string =>字符串

：datetime => DateTime

我认为Rails可以使用规范的查找列表，但似乎找不到。理想情况下，我会找到一种适用于Rails支持的每个数据库适配器的方法。

Answer 1

您可以找到PostgreSQL in the source code on the official repo的“类型匹配”。

NATIVE_DATABASE_TYPES = {
        primary_key: "bigserial primary key",
        string:      { name: "character varying" },
        text:        { name: "text" },
        integer:     { name: "integer", limit: 4 },
        float:       { name: "float" },
        decimal:     { name: "decimal" },
        datetime:    { name: "timestamp" },
        time:        { name: "time" },
        date:        { name: "date" },
        daterange:   { name: "daterange" },
        numrange:    { name: "numrange" },
        tsrange:     { name: "tsrange" },
        tstzrange:   { name: "tstzrange" },
        int4range:   { name: "int4range" },
        int8range:   { name: "int8range" },
        binary:      { name: "bytea" },
        boolean:     { name: "boolean" },
        xml:         { name: "xml" },
        tsvector:    { name: "tsvector" },
        hstore:      { name: "hstore" },
        inet:        { name: "inet" },
        cidr:        { name: "cidr" },
        macaddr:     { name: "macaddr" },
        uuid:        { name: "uuid" },
        json:        { name: "json" },
        jsonb:       { name: "jsonb" },
        ltree:       { name: "ltree" },
        citext:      { name: "citext" },
        point:       { name: "point" },
        line:        { name: "line" },
        lseg:        { name: "lseg" },
        box:         { name: "box" },
        path:        { name: "path" },
        polygon:     { name: "polygon" },
        circle:      { name: "circle" },
        bit:         { name: "bit" },
        bit_varying: { name: "bit varying" },
        money:       { name: "money" },
        interval:    { name: "interval" },
        oid:         { name: "oid" },
}

我还要补充一点，那就是了解事情的幕后运作确实是一件好事，ORM的目标之一就是让您不必在意。您应该在迁移中使用ruby数据类型。

如果您要使用跨数据库解决方案，只需避免在每个DBMS上使用与之不匹配的类型（例如:decimal）

如何使用Active Record从PostgreSQL类型获取Ruby类型

1 个答案: