数据迁移

common/src/main/ets/dbflow/Migration.ets

+import rdb from '@ohos.data.relationalStore'
+import { Logger } from '../utils/Logger'
+/**
+ * 数据迁移类
+ */
+export class Migration {
+  /**
+   * 数据库名称
+   */
+  private dbName: string = "";
+  /**
+   * 数据库表名
+   */
+  private tableName: string = "";
+
+  /**
+   * 数据库版本（默认：1）
+   */
+  private dbVersion: number = 1;
+
+  /**
+   * 对表进行修改的Alter语句(ALTER TABLE 语句用于在已有的表中添加、修改或删除列)
+   */
+  private alters: string = "";
+
+  /**
+   * @param dbName    数据库名称
+   * @param tableName 表名称
+   * @param dbVersion 数据库版本
+   */
+  constructor(dbName: string, tableName: string, dbVersion: number) {
+    this.tableName = tableName;
+    this.dbName = dbName;
+    this.dbVersion = dbVersion;
+  }
+
+  /**
+   * 新增列操作
+   */
+  addColumn(columnName: string, columnType: string): any {
+    if (this.alters == "") {
+      this.alters = "alter table " + this.tableName + " add " + columnName + " " + columnType;
+    }
+    return this;
+  }
+
+  /**
+   * 修改列操作(需要修改的列名以及列数据类型名称,返回当前类实例)
+   */
+  updateColumn(columnName: string, columnType: string): any {
+    if (this.alters == "") {
+      this.alters = "alter table " + this.tableName + " alter column " + columnName + " " + columnType;
+    }
+    return this;
+  }
+
+  /**
+   * 删除列操作(需要删除的列名,返回当前类实例)
+   */
+  deleteColumn(columnName: string): any {
+    if (this.alters == "") {
+      this.alters = "alter table " + this.tableName + " drop column " + columnName;
+    }
+    return this;
+  }
+
+  /**
+   * 列操作
+   */
+  Alter(alters: string): any {
+    if (this.alters != "") {
+      this.alters = ""
+    }
+    this.alters = alters;
+    return this;
+  }
+
+  /**
+   * 执行操作并升级数据库
+   * @param context
+   * @param encrypt
+   */
+  public execute(context: any, encrypt: boolean): any {
+    let that = this;
+    rdb.getRdbStore(context, {
+      name: that.dbName,
+      securityLevel: rdb.SecurityLevel.S1,
+      encrypt: encrypt
+    }, (err, rdbStore) => {
+      if (err) {
+        Logger.info(this, '[数据迁移失败]|错误信息:' + err)
+      } else {
+        rdbStore.executeSql(that.alters, null, () => {
+          Logger.info(this, '数据迁移完成')
+        })
+      }
+    })
+    return this;
+  }
+
+  /**
+   * 异步执行操作并升级数据库
+   * @param context
+   * @param encrypt
+   */
+  public async executeAsync(context: any, encrypt: boolean): Promise<any> {
+    let rdbStore: rdb.RdbStore = await rdb.getRdbStore(context, {
+      name: this.dbName,
+      securityLevel: rdb.SecurityLevel.S1,
+      encrypt: encrypt
+    })
+    await rdbStore.executeSql(this.alters, null);
+    Logger.info(this, '数据迁移完成')
+    return this;
+  }
+}
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