SQLITEASSETHELPER正確的升級腳本

Question

我不明白這些文檔，我擔心在我的數據庫中不小心丟掉了我的表格，並且如果我做錯了，會損壞原始文件。

https://github.com/jgilfelt/android-sqlite-asset-helper

在參考與值添加列。下面的代碼通過創混帳樞紐樣品

-- add a FullNames column to Employees 
ALTER TABLE "Employees" RENAME TO 'Employees_ME_TMP'; 

CREATE TABLE "Employees" 
(
    "EmployeeID" int NOT NULL, 
    "LastName" varchar(20) NOT NULL, 
    "FirstName" varchar(10) NOT NULL, 
    "FullName" varchar(150), 
    PRIMARY KEY ("EmployeeID") 
); 

INSERT INTO "Employees" 
(
    "EmployeeID", 
    "LastName", 
    "FirstName", 
    "FullName" 
) 
SELECT 
    "EmployeeID", 
    "LastName", 
    "FirstName", 
    "FirstName" || ' ' || "LastName" 
FROM 
    "Employees_ME_TMP"; 

DROP TABLE "Employees_ME_TMP"; 

如果我需要添加兩列，然後插入一堆值到那些列，這會是正確的語法提供？

-- add a FullNames column and NickName to Employees 
ALTER TABLE "Employees" RENAME TO 'Employees_ME_TMP'; 

CREATE TABLE "Employees" 
(
    "EmployeeID" int NOT NULL, 
    "LastName" varchar(20) NOT NULL, 
    "FirstName" varchar(10) NOT NULL, 
    "FullName" varchar(150), 
    "NickName" varchar(150), 
    PRIMARY KEY ("EmployeeID") 
); 

    INSERT INTO Employees (FullName, NickName) 
    VALUES ('Tyler Durden','Jack') 
    WHERE rowid = 18; 

    INSERT INTO Employees (FullName, NickName) 
    VALUES ('Donnie Darko','Jake') 
    WHERE rowid = 19; 

DROP TABLE "Employees_ME_TMP"; 

Answer 1

的documentation說：

INSERT語句......在現有的表創建一個或多個新行。

您的新表爲空，所以您實際上需要創建行，但這些行中的數據必須來自舊錶。所以，你必須使用INSERT語句的SELECT形式：

INSERT INTO Employees(EmployeeID, LastName, FirstName) 
SELECT EmployeeID, LastName, FirstName FROM Employees_ME_TMP; 

在INSERT未提及的其他列將（在這種情況下，NULL）來填充其默認值。 然後，您必須將新值放入這些列中。 更改行與UPDATE statement完成：

UPDATE Employees 
SET FullName = 'Tyler Durden', 
    NickName = 'Jack' 
WHERE EmployeeID = 18; 

UPDATE Employees 
SET FullName = 'Donnie Darko', 
    NickName = 'Jake' 
WHERE EmployeeID = 19;