AddCheckConstraint ✔ (重建) AddColumn ✔ AddForeignKey ✔ (重建) AddPrimaryKey ✔ (重建) AddUniqueConstraint ✔ (重建) AlterColumn ✔ (重建) CreateIndex ✔ CreateTable ✔ DropCheckConstraint ✔ (重建) DropColumn ✔ (重建) DropForeignKey ✔ (重建) DropIndex ✔ DropPrimary...
-- (1)增加列(字段) alter table tab_name add [column] 列名 类型[完整性约束条件][first|after 字段名]; #添加多个字段 alter table users2 add addr varchar(20), add age int first, add birth varchar(20) after name; -- (2)修改一列类型 alter table tab_name modify 列名 类型 [完整性约束...
sqlite错误 Abort due to constraint violation column id is not unique id没开启自动增长
Install a recent version of Cordova CLI, create a simple app with no plugins, and run it on the desired target platforms. Add a very simple plugin such as cordova-plugin-dialogs or an echo plugin and get it working. Ideally you should be able to handle a callback with some data coming...
@Index 为相应的数据库列[column]创建数据库索引[index]。如果不想使用 greenDAO 为该属性生成的默认索引名称,可通过name设置;向索引添加UNIQUE约束,强制所有值是唯一的。 java //可以用来:1、指定应对属性编制索引;2、通过 Entity 的 indexes() 定义多列索引 @Target(ElementType.FIELD) public @interface Index ...
Column("_id")] public int Id { get; set; } [MaxLength(250), Unique] public...
"unique"(default = false): Does the column have a unique constraint? "default": The default value of the column if not explicitly given. "primary_key"(default = false): Is this the primary key of this table? Evidently, only a single column can be set as the primary key. ...
db.open()){qDebug()<<db.lastError();qFatal("Failed to connect.");}qDebug("Connected!");//各种操作QSqlQuery qry;//创建tableqry.prepare("CREATE TABLE IF NOT EXISTS names (id INTEGER UNIQUE PRIMARY KEY, firstname VARCHAR(30), lastname VARCHAR(30))");if(!qry.exec())qDebug()<<qry...
To create a column you have to pass two arguments at least: its name in the table and your mapped class member pointer. You can also add extra arguments to tell your storage about column's constraints like primary_key, autoincrement, default_value, unique or generated_always_as (order isn...
In SQLite, there are different constraints, which restrict the data of the column by some rules, when the data is inserted, updated, or modified. Some of the common constraints of the databases which are supported by SQLite are UNIQUE, PRIMARY KEY, FOREI