gliderecord-patterns

ServiceNow 的 GlideRecord 最佳实践

GlideRecord 是 ServiceNow 中用于数据库操作的主要 API。遵循这些模式可确保查询高效且安全。

基本查询模式

按 sys_id 获取单条记录

var gr = new GlideRecord("incident")
if (gr.get("sys_id_here")) {
  gs.info("Found: " + gr.getValue("number"))
}

按字段获取单条记录

var gr = new GlideRecord("sys_user")
if (gr.get("user_name", "admin")) {
  gs.info("Found user: " + gr.getValue("name"))
}

查询多条记录

var gr = new GlideRecord("incident")
gr.addQuery("active", true)
gr.addQuery("priority", "1")
gr.orderByDesc("sys_created_on")
gr.setLimit(100)
gr.query()

while (gr.next()) {
  gs.info(gr.getValue("number"))
}

编码查询（更快）

对于复杂条件，请使用编码查询——它们比多次调用 addQuery 更高效：

var gr = new GlideRecord("incident")
// Encoded query from list view URL or Query Builder
gr.addEncodedQuery("active=true^priority=1^assigned_toISEMPTY")
gr.query()

while (gr.next()) {
  // Process records
}

性能提示

1. 始终使用 setLimit()

// When you only need X records
var gr = new GlideRecord("incident")
gr.addQuery("active", true)
gr.setLimit(10) // Don't fetch more than needed
gr.query()

2. 对字符串使用 getValue()

// CORRECT - Returns string value
var number = gr.getValue("number")

// ALSO WORKS but returns GlideElement
var element = gr.number
var numberStr = gr.number.toString()

3. 对引用字段使用 getDisplayValue()

// Get the display value of a reference field
var assignedToName = gr.getDisplayValue("assigned_to")

// Get the sys_id of a reference field
var assignedToId = gr.getValue("assigned_to")

4. 避免在循环中查询

// BAD - Query inside loop
for (var i = 0; i < userIds.length; i++) {
  var gr = new GlideRecord("sys_user")
  gr.get(userIds[i]) // N queries!
}

// GOOD - Single query with IN clause
var gr = new GlideRecord("sys_user")
gr.addQuery("sys_id", "IN", userIds.join(","))
gr.query()
while (gr.next()) {
  // Process all users at once
}

5. 使用 GlideAggregate 统计数量

// BAD - Counting with GlideRecord
var count = 0
var gr = new GlideRecord("incident")
gr.addQuery("active", true)
gr.query()
while (gr.next()) {
  count++
}

// GOOD - Use GlideAggregate
var ga = new GlideAggregate("incident")
ga.addQuery("active", true)
ga.addAggregate("COUNT")
ga.query()
if (ga.next()) {
  var count = ga.getAggregate("COUNT")
}

CRUD 操作

插入

var gr = new GlideRecord("incident")
gr.initialize()
gr.setValue("short_description", "New incident")
gr.setValue("caller_id", gs.getUserID())
gr.setValue("priority", "3")
var sysId = gr.insert()

更新

var gr = new GlideRecord("incident")
if (gr.get("sys_id_here")) {
  gr.setValue("state", "6") // Resolved
  gr.setValue("close_notes", "Issue fixed")
  gr.update()
}

删除（谨慎使用！）

var gr = new GlideRecord("incident")
if (gr.get("sys_id_here")) {
  gr.deleteRecord()
}

批量更新

var gr = new GlideRecord("incident")
gr.addQuery("state", "6") // Resolved
gr.addQuery("resolved_at", "<", gs.daysAgoStart(30))
gr.query()

while (gr.next()) {
  gr.setValue("state", "7") // Closed
  gr.update()
}

查询运算符

运算符	示例	说明
=	addQuery('active', true)	等于
!=	addQuery('active', '!=', true)	不等于
>, <	addQuery('priority', '<', '3')	大于／小于
>=, <=	addQuery('sys_created_on', '>=', gs.daysAgoStart(7))	大于／小于或等于
CONTAINS	addQuery('short_description', 'CONTAINS', 'error')	包含字符串
STARTSWITH	addQuery('number', 'STARTSWITH', 'INC')	以……开头
ENDSWITH	addQuery('email', 'ENDSWITH', '@company.com')	以……结尾
IN	addQuery('state', 'IN', '1,2,3')	在列表中
NOT IN	addQuery('state', 'NOT IN', '6,7')	不在列表中
ISEMPTY	addQuery('assigned_to', 'ISEMPTY', '')	字段为空
ISNOTEMPTY	addQuery('assigned_to', 'ISNOTEMPTY', '')	字段不为空

安全注意事项

1. setWorkflow(false) - 批量操作时跳过业务规则
2. setLimit() - 防止查询失控
3. 检查 canRead()/canWrite() - 验证 ACL 权限
4. 切勿信任用户输入 - 在查询中使用前先进行验证