创建上下文验证规则
本操作指南演示如何使用验证上下文创建验证规则，以检查跨多个对象的条件。这些规则仅用于演示，并不一定反映 Metric Views 或 Semantic Bridge 的硬性技术要求。
Note
这些操作指南适用于 Tabular Editor 3.26.2 及更高版本。早期版本不支持此处所示的 v1.1 Metric View 功能。
何时使用上下文规则
在需要执行以下操作时，请使用上下文规则：
- 检查名称是否在不同对象类型之间重复使用
- 访问先前已验证对象的信息
Note
验证过程会按顺序验证每个 Metric View 对象（先验证连接，再验证字段，最后验证度量值），因此上下文仅包含在本次验证中已访问过的项。
MakeValidationRule 方法
泛型方法 MakeValidationRule<T> 可用于访问验证上下文：
using MetricView = TabularEditor.SemanticBridge.Platforms.Databricks.MetricView;
SemanticBridge.MetricView.MakeValidationRule<MetricView.Measure>( // or Field, Join, View
"rule_name",
"category",
// return an IEnumerable<DiagnosticMessage>;
// an empty collection means the object passed
(obj, context) => []
);
context 参数提供以下内容：
context.FieldNames- 已验证的字段名称context.MeasureNames- 已验证的度量值名称列表context.JoinNames- 已验证的连接名称context.MakeError(code, message, object)- 为给定对象创建一条错误诊断信息context.MakeWarning(code, message, object)- 为给定对象创建一条警告诊断信息
由于诊断信息是在验证函数体内创建的，你可以在信息中加入当前正在验证对象的详细信息。
Metric View 类型的 using 指令
添加以下 using 指令以引用 Metric View 类型：
using MetricView = TabularEditor.SemanticBridge.Platforms.Databricks.MetricView;
规则：Metric View 度量值名称不得与 Metric View 字段名称重复
字段会先于度量值进行验证，因此在检查度量值时，context.FieldNames 已包含所有字段名称。
using MetricView = TabularEditor.SemanticBridge.Platforms.Databricks.MetricView;
var measureNameRule = SemanticBridge.MetricView.MakeValidationRule<MetricView.Measure>(
"measure_not_field_name",
"naming",
(measure, context) =>
context.FieldNames.Contains(measure.Name)
? [context.MakeError(
"measure_field_name_collision",
$"Measure '{measure.Name}' has the same name as a field",
measure)]
: []
);
规则：Metric View 度量值名称不得与 Metric View 连接名称重复
连接会最先进行验证，因此在检查度量值时，context.JoinNames 已包含所有连接名称。
using MetricView = TabularEditor.SemanticBridge.Platforms.Databricks.MetricView;
var measureNotJoinRule = SemanticBridge.MetricView.MakeValidationRule<MetricView.Measure>(
"measure_not_join_name",
"naming",
(measure, context) =>
context.JoinNames.Contains(measure.Name)
? [context.MakeError(
"measure_join_name_collision",
$"Measure '{measure.Name}' has the same name as a join",
measure)]
: []
);
为什么拆分规则更好
注意，我们创建了两条独立的规则，而不是把它们合并成一条规则。推荐这样做，原因是：
- 更清晰的错误信息：每条规则都会生成明确、可操作的信息
- 更易维护：规则可以独立新增、移除或修改
- 逻辑更简单：每条规则只检查一个条件
- 更便于分类：规则可以按用途分组和筛选
完整示例
此 Metric View 存在命名冲突，将同时触发这两条上下文规则：
using MetricView = TabularEditor.SemanticBridge.Platforms.Databricks.MetricView;
// Create a Metric View with names reused across object types
SemanticBridge.MetricView.Deserialize("""
version: 1.1
source: sales.fact.orders
joins:
- name: customer
source: sales.dim.customer
on: source.customer_id = customer.customer_id
cardinality: many_to_one
fields:
# 'revenue' is also used as a measure name below
- name: revenue
expr: source.revenue
- name: quantity
expr: source.quantity
measures:
# measureNameRule violation - same name as the 'revenue' field
- name: revenue
expr: SUM(source.revenue)
# measureNotJoinRule violation - same name as the 'customer' join
- name: customer
expr: COUNT(DISTINCT source.customer_id)
# this measure is fine
- name: order_count
expr: COUNT(source.order_id)
""");
var measureNameRule = SemanticBridge.MetricView.MakeValidationRule<MetricView.Measure>(
"measure_not_field_name",
"naming",
(measure, context) =>
context.FieldNames.Contains(measure.Name)
? [context.MakeError(
"measure_field_name_collision",
$"Measure '{measure.Name}' has the same name as a field",
measure)]
: []
);
var measureNotJoinRule = SemanticBridge.MetricView.MakeValidationRule<MetricView.Measure>(
"measure_not_join_name",
"naming",
(measure, context) =>
context.JoinNames.Contains(measure.Name)
? [context.MakeError(
"measure_join_name_collision",
$"Measure '{measure.Name}' has the same name as a join",
measure)]
: []
);
// Run validation with both rules
var diagnostics = SemanticBridge.MetricView.Validate([
measureNameRule,
measureNotJoinRule
]).ToList();
// Output results
var sb = new System.Text.StringBuilder();
sb.AppendLine("CONTEXTUAL VALIDATION RESULTS");
sb.AppendLine("-----------------------------");
sb.AppendLine("");
sb.AppendLine($"Found {diagnostics.Count} issue(s):");
sb.AppendLine("");
foreach (var diag in diagnostics)
{
sb.AppendLine($"[{diag.Severity}] {diag.Message}");
}
Output(sb.ToString());
输出：
CONTEXTUAL VALIDATION RESULTS
-----------------------------
Found 2 issue(s):
[Error] Measure 'revenue' has the same name as a field
[Error] Measure 'customer' has the same name as a join
与默认规则组合
你可以通过调用两次 Validate，将上下文规则与默认验证规则一起运行：
using MetricView = TabularEditor.SemanticBridge.Platforms.Databricks.MetricView;
var customRules = new[] {
SemanticBridge.MetricView.MakeValidationRule<MetricView.Measure>(
"measure_not_field_name",
"naming",
(measure, context) =>
context.FieldNames.Contains(measure.Name)
? [context.MakeError(
"measure_field_name_collision",
$"Measure '{measure.Name}' has the same name as a field",
measure)]
: []),
SemanticBridge.MetricView.MakeValidationRule<MetricView.Measure>(
"measure_not_join_name",
"naming",
(measure, context) =>
context.JoinNames.Contains(measure.Name)
? [context.MakeError(
"measure_join_name_collision",
$"Measure '{measure.Name}' has the same name as a join",
measure)]
: [])
};
// Run default rules first
var defaultDiagnostics = SemanticBridge.MetricView.Validate().ToList();
// Then run custom rules
var customDiagnostics = SemanticBridge.MetricView.Validate(customRules).ToList();
var sb = new System.Text.StringBuilder();
sb.AppendLine($"Default rule issues: {defaultDiagnostics.Count}");
sb.AppendLine($"Custom rule issues: {customDiagnostics.Count}");
Output(sb.ToString());
输出
Default rule issues: 0
Custom rule issues: 2