Go錯誤：time.Time未實作driver.Valuer（缺少方法Value）

php小編子墨在使用Go語言開發過程中，可能會遇到一個常見的錯誤：「Go錯誤：time.Time未實作driver.Valuer（缺少方法Value ）」。這個錯誤通常在將time.Time類型的值儲存到資料庫中時出現。它表明time.Time類型沒有實作driver.Valuer接口，並且缺少Value方法。解決這個問題的方法有很多，我們可以透過自訂新的時間類型，或是使用第三方函式庫來處理時間類型的儲存。在本文中，我們將詳細介紹這個錯誤的原因和解決方案，幫助開發者更好地理解和解決這個問題。

問題內容

我正在開發一個 Go 項目，在該項目中，我使用 sqlboiler 從我使用 setup.sh 腳本創建的 SQLite3 資料庫生成程式碼。我遇到了一個似乎無法解決的錯誤。錯誤訊息是：

graph/db/repositories.go:998:23: cannot use o.CreatedAt (variable of type string) as driver.Valuer value in argument to queries.MustTime: string does not implement driver.Valuer (missing method Value)
graph/db/repositories.go:999:23: cannot use &o.CreatedAt (value of type *string) as sql.Scanner value in argument to queries.SetScanner: *string does not implement sql.Scanner (missing method Scan)

當我嘗試在 graph/db/repositories.go 檔案中使用 time.Time 值時，會發生此錯誤。我正在為我的專案使用 golang:1.21-alpine3.18 Docker 映像。

我嘗試更改 SQLite3 資料庫的儲存庫表中的created_at 列類型。我已經使用 TEXT 和 TIMESTAMP 資料類型對其進行了測試，但錯誤仍然存在。

有誰知道可能導致此錯誤的原因以及如何解決它？

repositories.go

func (o *Repository) Insert(ctx context.Context, exec boil.ContextExecutor, columns boil.Columns) error {
    if o == nil {
        return errors.New("db: no repositories provided for insertion")
    }

    var err error
    if !boil.TimestampsAreSkipped(ctx) {
        currTime := time.Now().In(boil.GetLocation())

        if queries.MustTime(o.CreatedAt).IsZero() {
            queries.SetScanner(&o.CreatedAt, currTime)
        }
    }

    if err := o.doBeforeInsertHooks(ctx, exec); err != nil {
        return err
    }

    nzDefaults := queries.NonZeroDefaultSet(repositoryColumnsWithDefault, o)

    key := makeCacheKey(columns, nzDefaults)
    repositoryInsertCacheMut.RLock()
    cache, cached := repositoryInsertCache[key]
    repositoryInsertCacheMut.RUnlock()

setup.sh

#!/usr/local/bin/sh

set -eu

readonly DBFILE_NAME="mygraphql.db"

# Create DB file
if [ ! -e ${DBFILE_NAME} ];then
  echo ".open ${DBFILE_NAME}" | sqlite3
fi

# Create DB Tables
echo "creating tables..."
sqlite3 ${DBFILE_NAME} "
PRAGMA foreign_keys = ON;

CREATE TABLE IF NOT EXISTS users(\
    id TEXT PRIMARY KEY NOT NULL,\
    name TEXT NOT NULL,\
    project_v2 TEXT\
);

CREATE TABLE IF NOT EXISTS repositories(\
    id TEXT PRIMARY KEY NOT NULL,\
    owner TEXT NOT NULL,\
    name TEXT NOT NULL,\
    created_at TEXT NOT NULL DEFAULT (DATETIME('now','localtime')),\
    FOREIGN KEY (owner) REFERENCES users(id)\
);

CREATE TABLE IF NOT EXISTS issues(\
    id TEXT PRIMARY KEY NOT NULL,\
    url TEXT NOT NULL,\
    title TEXT NOT NULL,\
    closed INTEGER NOT NULL DEFAULT 0,\
    number INTEGER NOT NULL,\
    repository TEXT NOT NULL,\
    CHECK (closed IN (0, 1)),\
    FOREIGN KEY (repository) REFERENCES repositories(id)\
);

CREATE TABLE IF NOT EXISTS projects(\
    id TEXT PRIMARY KEY NOT NULL,\
    title TEXT NOT NULL,\
    url TEXT NOT NULL,\
    owner TEXT NOT NULL,\
    FOREIGN KEY (owner) REFERENCES users(id)\
);

CREATE TABLE IF NOT EXISTS pullrequests(\
    id TEXT PRIMARY KEY NOT NULL,\
    base_ref_name TEXT NOT NULL,\
    closed INTEGER NOT NULL DEFAULT 0,\
    head_ref_name TEXT NOT NULL,\
    url TEXT NOT NULL,\
    number INTEGER NOT NULL,\
    repository TEXT NOT NULL,\
    CHECK (closed IN (0, 1)),\
    FOREIGN KEY (repository) REFERENCES repositories(id)\
);

CREATE TABLE IF NOT EXISTS projectcards(\
    id TEXT PRIMARY KEY NOT NULL,\
    project TEXT NOT NULL,\
    issue TEXT,\
    pullrequest TEXT,\
    FOREIGN KEY (project) REFERENCES projects(id),\
    FOREIGN KEY (issue) REFERENCES issues(id),\
    FOREIGN KEY (pullrequest) REFERENCES pullrequests(id),\
    CHECK (issue IS NOT NULL OR pullrequest IS NOT NULL)\
);
"

# Insert initial data
echo "inserting initial data..."
sqlite3 ${DBFILE_NAME} "
PRAGMA foreign_keys = ON;

INSERT INTO users(id, name) VALUES\
    ('U_1', 'hsaki')
;

INSERT INTO repositories(id, owner, name) VALUES\
    ('REPO_1', 'U_1', 'repo1')
;

INSERT INTO issues(id, url, title, closed, number, repository) VALUES\
    ('ISSUE_1', 'http://example.com/repo1/issue/1', 'First Issue', 1, 1, 'REPO_1'),\
    ('ISSUE_2', 'http://example.com/repo1/issue/2', 'Second Issue', 0, 2, 'REPO_1'),\
    ('ISSUE_3', 'http://example.com/repo1/issue/3', 'Third Issue', 0, 3, 'REPO_1')\
;

INSERT INTO projects(id, title, url, owner) VALUES\
    ('PJ_1', 'My Project', 'http://example.com/project/1', 'U_1')\
;

INSERT INTO pullrequests(id, base_ref_name, closed, head_ref_name, url, number, repository) VALUES\
    ('PR_1', 'main', 1, 'feature/kinou1', 'http://example.com/repo1/pr/1', 1, 'REPO_1'),\
    ('PR_2', 'main', 0, 'feature/kinou2', 'http://example.com/repo1/pr/2', 2, 'REPO_1')\
;
"

sqlboiler.toml

pkgname="db"
output="graph/db"
wipe=true
add-global-variants=false
no-tests=true

[sqlite3]
  dbname = "./mygraphql.db"

環境

・ MacBook Pro M1 Pro

解決方法

我會說更新 Go 中的儲存庫結構，將 CreatedAt 作為 time.Time 欄位。 將值指派給 CreatedAt 時，請使用 time.Time 值。例如， currTime := time.Now() 讓你的結構像這樣

type Repository struct {
    ID        string    `boil:"id" json:"id" toml:"id" yaml:"id"`
    Owner     string    `boil:"owner" json:"owner" toml:"owner" yaml:"owner"`
    Name      string    `boil:"name" json:"name" toml:"name" yaml:"name"`
    CreatedAt time.Time `boil:"created_at" json:"created_at" toml:"created_at" yaml:"created_at"`
    // other fields...
}

然後設定 CreatedAt 值：

repository := &Repository{
    ID:        "some-id",
    Owner:     "owner-id",
    Name:      "repo-name",
    CreatedAt: time.Now(), // setting it as time.Time
}

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