项目构建时间过长，添加复杂查询后运行

Question

我已经在我的一个 swift 项目中集成了 SQLite.swift 框架，在我添加以下查询之前一切正常。添加以下查询项目后构建时间过长。我等了 30 分钟，但项目仍然不符合。

do
{
let stmt = try DB!.prepare ("SELECT e." + ENDPOINT_ID + " as _id, lk." + HUB_ID + ", e." + X_ENDPOINT_ID + ", e." + ENDPOINT_DESC + ", e." + ENDPOINT_TYPE_ID +", et." + ENDPOINT_STATUS_MIN + ", et." + ENDPOINT_STATUS_MAX + ", e." + ENDPOINT_STATUS + " FROM " + TABLE_ENDPOINT + " as e INNER JOIN " + TABLE_ENDPOINT_TYPE + " as et " +
" ON e." + ENDPOINT_TYPE_ID + " = et." + ENDPOINT_TYPE_ID +
" INNER JOIN " + TABLE_LINKING + " as lk " +
" ON e." + ENDPOINT_ID + " = lk." + ENDPOINT_ID +
" INNER JOIN " + TABLE_NODE + " as n " +
" ON lk." + NODE_ID + " = n." + NODE_ID +
" INNER JOIN " + TABLE_NODE_TYPE + " as nt " +
" ON n." + NODE_TYPE_ID + " = nt." + NODE_TYPE_ID +
" WHERE lk." + SECTION_ID + "=" + section_Id +
" AND nt." + NODE_CATEGORY + " = "S" " +
" ORDER BY e." + ENDPOINT_ID + " ASC")

        let arr = Array(try stmt.run)

        print("\(arr)")
        return arr
    } catch {
        print("failed: \(error)")
        return []
    }

如果我评论上面的代码并尝试运行项目运行几乎不需要一分钟，但在添加此代码后，它会花费很多时间。我已经等了将近 30 分钟，但项目仍然没有编译，也没有抛出任何错误。在此先感谢您的帮助

Answer 1

Swift 编译器很难处理大字符串文字。另请参阅 this question 以获取更多提示。

我建议拆分 sql 并逐步构建一个字符串变量：

var sql = "SELECT e." + ENDPOINT_ID
sql = sql + HUB_ID + ", e."
sql = sql + X_ENDPOINT_ID + ", e."
...
let stmt = try DB!.prepare(sql)

Answer 2

  let query = (TABLE_ENDPOINT.select(TABLE_ENDPOINT[ENDPOINT_ID], TABLE_LINKING[HUB_ID], TABLE_ENDPOINT[ETCT_ENDPOINT_ID], TABLE_ENDPOINT[ENDPOINT_DESC], TABLE_ENDPOINT[ENDPOINT_TYPE_ID], TABLE_ENDPOINT_TYPE[ENDPOINT_STATUS_MIN], TABLE_ENDPOINT_TYPE[ENDPOINT_STATUS_MAX], TABLE_ENDPOINT[ENDPOINT_STATUS]).join(TABLE_ENDPOINT_TYPE, on: TABLE_ENDPOINT[ENDPOINT_TYPE_ID] == TABLE_ENDPOINT_TYPE[ENDPOINT_TYPE_ID]).join(TABLE_LINKING, on: TABLE_ENDPOINT[ENDPOINT_ID] == TABLE_LINKING[ENDPOINT_ID]).join(TABLE_NODE, on: TABLE_LINKING[NODE_ID] == TABLE_NODE[NODE_ID]).join(TABLE_NODE_TYPE, on: TABLE_NODE[NODE_TYPE_ID] == TABLE_NODE_TYPE[NODE_TYPE_ID])
                .filter(TABLE_LINKING[SECTION_ID] == section_Id && TABLE_NODE_TYPE[NODE_CATEGORY] == "S")
                .order(TABLE_ENDPOINT[ENDPOINT_ID].asc))

            let arr = Array(try DB!.prepare(query))

项目构建时间过长，添加复杂查询后运行

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项目构建时间过长，添加复杂查询后 运行

Project taking too long to build and run after adding complex query

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项目构建时间过长，添加复杂查询后运行