Question

我正在尝试使用node-postgres在我的postgres数据库中查询名为DOCUMENT的模式。

我似乎无法让查询针对指定的架构运行。

此查询使用psql直接针对postgres运行正常

SELECT * FROM "DOCUMENT".document_metadata m 
LEFT OUTER JOIN "DOCUMENT".document_attributes a 
ON a.document_id = m.id

此代码会在下面产生错误

const query = `SELECT * FROM "DOCUMENT".document_metadata m 
               LEFT OUTER JOIN "DOCUMENT".document_attributes a 
               ON a.document_id = m.id`
const metadata = await db.query(query)

错误

error: relation "DOCUMENT.document_metadata" does not exist
    at Connection.parseE (/usr/src/app/node_modules/pg/lib/connection.js:602:11)
    at Connection.parseMessage (/usr/src/app/node_modules/pg/lib/connection.js:399:19)
    at Socket.<anonymous> (/usr/src/app/node_modules/pg/lib/connection.js:121:22)
    at Socket.emit (events.js:189:13)
    at addChunk (_stream_readable.js:284:12)
    at readableAddChunk (_stream_readable.js:265:11)
    at Socket.Readable.push (_stream_readable.js:220:10)
    at TCP.onStreamRead [as onread] (internal/stream_base_commons.js:94:17)

我也尝试过

const query = `SET search_path TO 'DOCUMENT';
               SELECT * FROM document_metadata m 
               LEFT OUTER JOIN document_attributes a 
               ON a.document_id = m.id;`

const metadata = await db.query(query)

产生错误

error: relation "document_metadata" does not exist
    at Connection.parseE (/usr/src/app/node_modules/pg/lib/connection.js:602:11)
    at Connection.parseMessage (/usr/src/app/node_modules/pg/lib/connection.js:399:19)
    at Socket.<anonymous> (/usr/src/app/node_modules/pg/lib/connection.js:121:22)
    at Socket.emit (events.js:189:13)
    at addChunk (_stream_readable.js:284:12)
    at readableAddChunk (_stream_readable.js:265:11)
    at Socket.Readable.push (_stream_readable.js:220:10)
    at TCP.onStreamRead [as onread] (internal/stream_base_commons.js:94:17)

更新当我直接在psql中运行这些相同的查询时，我看到带有表名的10行。当我通过节点代码运行此命令时，我看不到任何行：

const metadata4 = await db.query('SHOW search_path;')
console.log('search_path after setting = ', metadata4.rows) // prints [ { search_path: '"DOCUMENT"' } ]

const tables = await db.query(`SELECT * FROM information_schema.tables where table_schema = 'DOCUMENT';`)
console.log('tables = ', tables.rows) // prints []

Answer 1

也许是大写问题。您是否尝试使用小写模式名称？或在表名周围添加引号：

const query = 'SELECT * FROM "DOCUMENT"."document_metadata" m 
               LEFT OUTER JOIN "DOCUMENT"."document_attributes" a 
               ON a.document_id = m.id'

在环境变量中将架构定义为客户端/池

无论如何，如果您想在节点js中定义模式，而无需在不同模式之间切换，那么solution是一个不错的选择。默认架构可以来自环境变量。

const Pool = require('pg').Pool
const Client = require('pg').Client

class EnhancedClient extends Client {
  getStartupConf() {
    if (process.env.PG_OPTIONS) {
      try {
        const options = JSON.parse(process.env.PG_OPTIONS);
        return {
          ...super.getStartupConf(),
          ...options,
        };
      } catch (e) {
        console.error(e);
        // Coalesce to super.getStartupConf() on parse error
      }
    }

    return super.getStartupConf();
  }
}

const pool = new Pool({
  Client: EnhancedClient,
  user: 'postgres',
  host: 'localhost',
  database: 'postgres',
  password: 'postgres',
  port: 5432
})

在此示例中，PG_OPTIONS是字符串化的JSON，例如通过命令行，PM2生态系统文件等提供。

例如：PG_OPTIONS='{"search_path":"DOCUMENT"}' node app.js

我从Windows命令提示符开始（对此很抱歉：））

SET PG_OPTIONS={"search_path":"DOCUMENT"}
node app.js

Answer 2

只需在单独的行中执行：

    $(document).on('click', '#printBtn', function () {
       window.print();
});

DOCUMENT是您的架构名称，然后执行常规查询：

db.query("SET search_path TO 'DOCUMENT';")

如何使用node-postgres设置架构

2 个答案:

在环境变量中将架构定义为客户端/池