feat(editor): preview dml changes as readonly select

apps/desktop/src/lib/sql/__tests__/dmlChangePreview.spec.ts

@@ -0,0 +1,20 @@
+import { describe, expect, it } from "vitest";
+import { looksLikeDmlStatement } from "../dmlChangePreview";
+
+describe("looksLikeDmlStatement", () => {
+  it("recognizes UPDATE / INSERT / DELETE statements", () => {
+    expect(looksLikeDmlStatement("UPDATE admin_sessions SET public_id = 123 WHERE id = 1")).toBe(true);
+    expect(looksLikeDmlStatement("  INSERT INTO t (a) VALUES (1)")).toBe(true);
+    expect(looksLikeDmlStatement("\nDELETE FROM t WHERE id = 2")).toBe(true);
+  });
+  it("ignores leading whitespace and preserves case-insensitivity", () => {
+    expect(looksLikeDmlStatement("   update t set a = 1")).toBe(true);
+    expect(looksLikeDmlStatement("Insert into t values (1)")).toBe(true);
+  });
+  it("rejects non-DML and unrelated statements", () => {
+    expect(looksLikeDmlStatement("SELECT * FROM t")).toBe(false);
+    expect(looksLikeDmlStatement("WITH x AS (SELECT 1) SELECT * FROM x")).toBe(false);
+    expect(looksLikeDmlStatement("")).toBe(false);
+    expect(looksLikeDmlStatement("CREATE TABLE t (a int)")).toBe(false);
+  });
+});

apps/desktop/src/lib/sql/dmlChangePreview.ts

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+/** 「预览变更」请求/响应的前端类型（对应后端 dml_preview_sql）。 */
+
+export interface DmlChangePreviewSqlOptions {
+  /** 用户写的一条 DML 语句（通常是当前语句）。 */
+  sql: string;
+  /** 连接类型（决定解析方言 / 默认标识符引号）。 */
+  databaseType?: string;
+  /** 连接的标识符引号字符（如 `"`、`` ` ``、`[`）。 */
+  identifierQuote?: string;
+  /** 目标表的列（ordinal）。提供且为单表 UPDATE 时，新值列紧跟其原值列。 */
+  columns?: string[];
+}
+
+export interface DmlChangePreviewTableRef {
+  catalog?: string;
+  database?: string;
+  schema?: string;
+  table?: string;
+}
+
+export interface DmlChangePreviewSqlResult {
+  /** 生成的只读 SELECT：在结果网格展示受影响行 + 「新值」列。 */
+  sql: string;
+  /** 语句类型：update / insert / delete。 */
+  operation: string;
+  /** 是否有「新值」列（仅 UPDATE 有）。 */
+  hasNewValueColumns: boolean;
+  /** 语句目标表引用（供前端拉取列元数据以交错展示新值列）。 */
+  tables: DmlChangePreviewTableRef[];
+}
+
+/** 从 SQL 文本粗略识别是否为可预览的 DML（用于「预览变更」入口显隐）。 */
+const DML_PREVIEW_RE = /^\s*(update|insert|delete)\b/i;
+
+export function looksLikeDmlStatement(sql: string): boolean {
+  return DML_PREVIEW_RE.test(sql);
+}