SQLite数据库表字段修改与删除
sinat_36572506 2016-11-01 13:41:25 7554 收藏
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我创建一张表,但是在使用过程中发现字段名称会发生改变,但是SQLite数据库只允许增加表字段(alter table my_table add field_name field_type;),不允许修改和删除表字段。这时候只能使用复制表思想了。步骤如下:
1、将需要修改的表(my_table)重新命名(ALTER TABLE "my_table" RENAME TO sqlitemanager_temp_table_11970396993;),
2、创建一个新的表命名为my_table,填入需要的字段名(CREATE TABLE "my_table" ("id" INTEGER PRIMARY KEY AUTOINCREMENT, "name" VARCHAR, "grender" VARCHAR DEFAULT "biao", "number" TEXT);)。
3、查询原来表(sqlitemanager_temp_table_11970396993)数据,向新创建的表(my_table)新增数据(INSERT INTO "my_table" ("id","name","grender","number") SELECT "id","name","grender","number" FROM sqlitemanager_temp_table_11970396993;)
4、销毁原来的表(sqlitemanager_temp_table_11970396993)
SQL语句实现如下:
PRAGMA foreign_keys = 0;
BEGIN TRANSACTION;
ALTER TABLE "my_table" RENAME TO sqlitemanager_temp_table_11970396993;
CREATE TABLE "my_table" ("id" INTEGER PRIMARY KEY AUTOINCREMENT, "name" VARCHAR, "grender" VARCHAR DEFAULT "biao", "number" TEXT DEFAULT "biao");
INSERT INTO "my_table" ("id","name","grender","number") SELECT "id","name","grender","number" FROM sqlitemanager_temp_table_11970396993;
DROP TABLE sqlitemanager_temp_table_11970396993;
COMMIT;
PRAGMA foreign_keys = 1;
修改字段名也是一样的思想.
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原文链接:https://blog.youkuaiyun.com/sinat_36572506/article/details/52995027