Flask Sql通过参数创建表

最新推荐文章于 2024-10-12 14:13:25 发布

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本文介绍了一种使用Python动态创建数据库表的方法，通过解析元数据字典来生成对应的数据表结构，并实现了批量设置属性的功能。

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# Integer,Float,String,DateTime

def getColumnObject(dbColumnDict):
    ctype = dbColumnDict["type"]
    isIdx = dbColumnDict["index"]
    if ctype == "String":
        n = dbColumnDict["length"]
        value = db.Column(db.String(n),index=isIdx)
    elif ctype == "Integer":
        value = db.Column(db.Integer,index=isIdx)
    elif ctype == "Float":
        value = db.Column(db.Float,index=isIdx)
    elif ctype == "DateTime":
        value = db.Column(db.DateTime,index=isIdx)
    else:
        raise Exception("No sucn type{}".format(ctype))
    return value

def createSetFunction():
    def f(self,attributeDict):
       for key in attributeDict.keys():
           self.__setattr__(key,attributeDict[key])
    return f

# metaDict{"tableName":,attributes:{name:{type:xxxx,index:True},name2:{}}
def createTableObject(metaDict):
    tableName = metaDict["tableName"]
    attrDict = {}
    attrDict["id"] = db.Column(db.Integer, primary_key=True)
    attrDict["timestamp"] = db.Column(db.DateTime, index=True, default=datetime.now)
    #attrList["user_id"] = db.Column(db.Integer, db.ForeignKey('user.id'))
    attrNames = []
    for name in metaDict['attributes'].keys():
        # Integer,Float,String,DateTime
        value = getColumnObject(metaDict['attributes'][name])
        attrDict[name] = value
        attrNames.append(name)

    print "type attr dict:",type(attrDict)
    TableClass = type(tableName,(db.Model,),attrDict)
    TableClass.setAll = createSetFunction()
    TableClass.column_name = attrNames
    # create one table
    TableClass.__table__.create(db.session.bind)
    return (tableName,TableClass)


@app.route("/test_db",methods=["GET"])
def test_db():
    try:
        metaDict = {"tableName":"test_db","attributes":{"count":{"type":"Integer","index":True}}}
        name , table_class = createTableObject(metaDict)
        record = table_class()
        record.setAll({"count":100,"user_id":current_user.get_id()})
        db.session.add(record)
        db.session.commit()

        return "add test db finished!"
    except Exception,e:
        return "TEST DB Exception {}".format(e)