用Genie在Sqlite数据库中创建表？

Question

我正在尝试使用Genie代码创建数据库。但是，我在文档方面遇到了问题，所以我在这里问！

这可以认为是不直观的，因为我可以直接在命令行上运行sqlite并创建数据集。我这样做是出于教义的原因。

我想在python中模仿的代码是：

#--------------------------------------
import apsw
#--------------------------------------
# Opening/creating database. Database name is cookbook.db3
connection=apsw.Connection("cookbook.db3")
cursor=connection.cursor()
#--------------------------------------
# Create The Tables
#--------------------------------------
sql = 'CREATE TABLE Recipes (pkiD INTEGER PRIMARY KEY, name TEXT, servings TEXT, source TEXT)'
cursor.execute(sql)
sql = 'CREATE TABLE Instructions (pkID INTEGER PRIMARY KEY, instructions TEXT, recipeID NUMERIC)'
cursor.execute(sql)
sql = 'CREATE TABLE Ingredients (pkID INTEGER PRIMARY KEY, ingredients TEXT, recipeID NUMERIC)'
cursor.execute(sql)
#--------------------------------------
# Insert Data into tables
#--------------------------------------
# Insert data into Recipe table
sql = 'INSERT INTO Recipes (name,servings,source) VALUES ("Spanish Rice",4,"Greg")'
cursor.execute(sql)
# Get the pkid for the inserted record
sql = "SELECT last_insert_rowid()"
cursor.execute(sql)
for x in cursor.execute(sql):
    lastid = x[0]
# Insert data into the instructions table
sql = 'INSERT INTO Instructions (recipeID,instructions) VALUES( %s,"Brown hamburger. Stir in all other ingredients. Bring to a boil. Stir. Lower to simmer. Cover and cook for 20 minutes or until all liquid is absorbed.")' % lastid
cursor.execute(sql)
# Insert data into the ingredients table
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"1 cup parboiled Rice (uncooked)")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"1 pound Hamburger")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"2 cups Water")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"1 8 oz can Tomato Sauce")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"1 small Onion chopped")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"1 clove Garlic chopped")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"1 tablespoon Ground Cumin")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"1 teaspoon Ground Oregano")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"Salt and Pepper to taste")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"Salsa to taste")' % lastid
cursor.execute(sql)
# Put in one more for good "measure"
sql = 'INSERT INTO Recipes (name,servings,source) VALUES ("Pickled Pepper-Onion Relish","9 half pints","Complete Guide to Home Canning")'
cursor.execute(sql)
# Get the pkid for the inserted record
sql = "SELECT last_insert_rowid()"
cursor.execute(sql)
for x in cursor.execute(sql):
    lastid = x[0]
sql = 'INSERT INTO Instructions (recipeID,instructions) VALUES( %s,"Wash and chop vegetables. Combine all ingredients and boil gently until mixture thickens and volume is reduced by 1/2 (about 30 minutes). Fill sterile jars with hot relish, leaving 1/2 inch head space and seal tightly. Store in refrigerator and use within one month or process in boiling water bath if extended storage is desired. Hot pack process time at 0-1000 feet for 5 minutes, 1,001 to 6000 ft 10 minutes, above 6,000 ft 15 minutes.")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"6 cups finely chopped Onions")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"3 cups finely chopped Red Peppers")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"3 cups finely chopped Green Peppers")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"1 1/2 cups sugar")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"6 cups White Vinegar (5 percent)")' % lastid
cursor.execute(sql)
sql = 'INSERT INTO Ingredients (recipeID,ingredients) VALUES ( %s,"2 tablespoons canning or pickling salt")' % lastid
cursor.execute(sql)
# Tell us we are done
print 'Done'

我已经学习了如何使用vala.doc，并找到了操作sqlite数据库的例程：Sqlite.Database。但是，我一直在编译时出错。

这是我重现该代码的程度：

/* HOW TO CREATE THE DB WITH GENIE */

// Opening/creating db.

[indent=4]
init
    Sqlite.Database db
    string errmsg

    int ec = Sqlite.Database.open("cookbook.db", out db)
    if ec != Sqlite.OK
        stderr.printf("Can't open database: %d: Ss\n", db.errcode(), db.errmesg)
        return -1

    // Insert data
    query:string ="""
        CREATE TABLE Recipes (pkiD INTEGER PRIMARY KEY, name TEXT, servings TEXT, source TEXT)
        """
    db.exec (query, null, out errmsg)

本来打算将表插入数据库，但出现以下错误：

    valac --pkg sqlite3 cookcreate.gs 
cookcreate.gs:9.11-9.11: error: syntax error, expected `:' but got `.' with previous identifier
    Sqlite.Database db
          ^
Compilation failed: 1 error(s), 0 warning(s)

任何帮助将不胜感激。

Answer 1

似乎您已经在Valadoc中使用了该示例，但是没有将类型信息从Vala语法转换为Genie语法。所以Sqlite.Database db会db:Sqlite.Database。

Genie中的一个有效示例是：

[indent=4]
init
    db:Sqlite.Database   
    errmsg:string

    ec:int = Sqlite.Database.open("cookbook.sqlite", out db)
    if ec != Sqlite.OK
        stderr.printf("Can't open database: %d: %s\n", db.errcode(), db.errmsg())
        Process.exit( -1 )

    query:string ="""CREATE TABLE Recipes (
        pkiD INTEGER PRIMARY KEY, 
        name TEXT,
        servings TEXT, 
        source TEXT 
        )
    """
    db.exec (query, null, out errmsg)

需要注意的几件事：

• 精灵只能返回成功的结果，因此return -1目前不允许。这可能会有所改变，请参见https://bugzilla.gnome.org/show_bug.cgi?id=707233。要解决此问题，可以使用GLib的Process.exit（），如上例所示。这样做的缺点是程序立即终止而不破坏对象。因此final，例如，如果您在类中使用它来关闭数据库连接，final则不会调用该块。或者，您也可以return，它总是返回0
• 逐字字符串“”"""I'm a verbatim string"""非常适合在Genie中嵌入SQL ：-)