prisma - prisma 是否支持 GeoSpatial 查询

Question

我发现您现在使用的是 MySQL 和 PostgreSQL，它们支持地理空间类型，我该如何对我的 prisma 执行地理空间查询。

假设我想获取纽约市附近的所有事件？

Answer 1

我使用 Prisma 和 MySQL 数据库在我的项目上“实现”了自定义地理搜索:

您需要能够以编程方式连接到您的数据库。

首先，让我们获取我们的env var:

const host = process.env.MYSQL_ENDPOINT;
const user = process.env.MYSQL_ROOT_USERNAME;
const password = process.env.MYSQL_ROOT_PASSWORD;
const database = process.env.PRISMA_SERVICE + "@" + process.env.PRISMA_STAGE;

现在尝试使用包 promise-mysql 连接到我们的数据库:

let connection;
try {
      //Create a connection to the database;
      connection = await mysql.createConnection({
        host,
        user,
        password,
        database
      });
    } catch (e) {
      console.error(e);
      throw new Error("Could not connect to the Database");
    }

需要在你的表中有一个空间列，它也应该有一个空间索引。可以使用这些(表必须为空)以编程方式执行此操作:

/**
* Add a spatial column to the table, used for geo-searching
 * @param  {string}  tableName name of the table to alter
 * @param  {string}  columnName name of the spatial column
 * @param  {string}  lonColumnName name of the longitude column
 * @param  {string}  latColumnName name of the latitude column
 * @param  {object}  connection connection to the database
 * @return {Promise} result of the table alteration
 */
 const addSpatialColumn = async (
  tableName,
  columnName,
  lonColumnName,
  latColumnName,
  connection
) => {
  return connection.query(`
  ALTER TABLE
      ${tableName} ADD ${columnName} POINT AS(
          ST_POINTFROMTEXT(
              CONCAT(
                  'POINT(',
                  ${lonColumnName},
                  ' ',
                  ${latColumnName},
                  ')'
              )
          )
      ) STORED NOT NULL;`);
};

/**
 * Add a spatial index to the table
 * @param  {string}  tableName  name of the table
 * @param  {string}  columnName name of the column to create an index on
 * @param  {object}  connection connection to the database
 * @return {Promise} result of the index creation
 */
const addSpatialIndex = async (tableName, columnName, connection) => {
  return connection.query(
    `ALTER TABLE ${tableName} ADD SPATIAL INDEX(${columnName});`
  );
};

现在是棘手的部分。由于 Prisma 尚未就此向我们灌输，您需要您自己确定您的 sql 查询的参数。

然后您可以进行查询，例如:

const query = `SELECT ${sqlSelect} FROM ${sqlFrom} WHERE 
MBRContains(ST_GeomFromText("${polygon}"), GeoPoint) ${sqlWhere} LIMIT 
${toSkip},${batchSize}`;

const selectedRows = await connection.query(query);

Post-scriptum : these snippets are not abstractions and therefore, may need modifications/improvements. I am just providing an example of a way to solve this temporary problem.