续集 model 排除 jsonb 字段中的子字段

Question

我有一个 postgresql 表，其结构有一个名为 external_data 的 jsonb 字段： external_data: {a: 1, b:2, c:3}

我知道在续集 model 定义中，您可以通过在选项属性中包含这样的 defaultScope 来排除字段：

{defaultScope: {attributes: { exclude: ['external_data'] }}

当我这样做以排除整个字段时，它会起作用，即 external_data 不会出现在返回的结果中。 但是，我想排除一个特定的子字段。 我试过exclude: ['external_data.b']但这似乎不起作用。

sequelize 是否允许排除 jsonb 字段中的子字段？ 如果是这样，排除属性的正确格式是什么？

Answer 1

来自文档： https://sequelize.org/v5/manual/scopes.html

范围在 model 定义中定义，可以是查找器对象，也可以是返回查找器对象的函数 - 除了默认的 scope，它只能是 object

因此，您可以通过返回查找器对象的 function 定义 scope，以便您可以实现复杂的 scope。

例如

import { sequelize } from '../../db';
import { Model, DataTypes, Op } from 'sequelize';

class TableA extends Model {}
TableA.init(
  {
    external_data: DataTypes.JSONB,
  },
  {
    sequelize,
    modelName: 'table_a',
    defaultScope: {
      attributes: { exclude: ['external_data'] },
    },
    scopes: {
      exclude(subField) {
        return {
          where: {
            external_data: {
              [subField]: {
                [Op.eq]: null,
              },
            },
          },
        };
      },
    },
  },
);

(async function test() {
  try {
    // create tables
    await sequelize.sync({ force: true });
    // seed
    await TableA.bulkCreate([
      { external_data: { a: 1, b: 2, c: 3 } },
      { external_data: { a: 10, c: 30 } },
      { external_data: { a: 100 } },
    ]);
    // test
    // test case 1: exclude subfield "b"
    const result1 = await TableA.scope({ method: ['exclude', 'b'] }).findAll({ raw: true });
    console.log('result1:', result1);
    // test case 2: exclude subfield "c"
    const result2 = await TableA.scope({ method: ['exclude', 'c'] }).findAll({ raw: true });
    console.log('result2:', result2);
  } catch (error) {
    console.log(error);
  } finally {
    await sequelize.close();
  }
})();

执行结果：

Executing (default): DROP TABLE IF EXISTS "table_a" CASCADE;
Executing (default): DROP TABLE IF EXISTS "table_a" CASCADE;
Executing (default): CREATE TABLE IF NOT EXISTS "table_a" ("id"   SERIAL , "external_data" JSONB, PRIMARY KEY ("id"));
Executing (default): SELECT i.relname AS name, ix.indisprimary AS primary, ix.indisunique AS unique, ix.indkey AS indkey, array_agg(a.attnum) as column_indexes, array_agg(a.attname) AS column_names, pg_get_indexdef(ix.indexrelid) AS definition FROM pg_class t, pg_class i, pg_index ix, pg_attribute a WHERE t.oid = ix.indrelid AND i.oid = ix.indexrelid AND a.attrelid = t.oid AND t.relkind = 'r' and t.relname = 'table_a' GROUP BY i.relname, ix.indexrelid, ix.indisprimary, ix.indisunique, ix.indkey ORDER BY i.relname;
Executing (default): INSERT INTO "table_a" ("id","external_data") VALUES (DEFAULT,'{"a":1,"b":2,"c":3}'),(DEFAULT,'{"a":10,"c":30}'),(DEFAULT,'{"a":100}') RETURNING *;
Executing (default): SELECT "id", "external_data" FROM "table_a" AS "table_a" WHERE ("table_a"."external_data"#>>'{b}') IS NULL;
result1: [ { id: 2, external_data: { a: 10, c: 30 } },
  { id: 3, external_data: { a: 100 } } ]
Executing (default): SELECT "id", "external_data" FROM "table_a" AS "table_a" WHERE ("table_a"."external_data"#>>'{c}') IS NULL;
result2: [ { id: 3, external_data: { a: 100 } } ]

检查数据库：

node-sequelize-examples=# select * from "table_a";
 id |      external_data
----+--------------------------
  1 | {"a": 1, "b": 2, "c": 3}
  2 | {"a": 10, "c": 30}
  3 | {"a": 100}
(3 rows)

依赖版本： "sequelize": "^5.21.3" , postgres:9.6

源代码： https://github.com/mrdulin/node-sequelize-examples/tree/master/src/examples/stackoverflow/61053931