importandroid.content.Context;importandroid.database.sqlite.SQLiteDatabase;importandroid.database.sqlite.SQLiteOpenHelper;importandroid.widget.Toast;importandroidx.annotation.Nullable;publicclassMyDatabaseHelperextendsSQLiteOpenHelper {publicstaticfinalString CREATE_BOOK = "create table Book (id integer primary key...
//改动2 添加改变表的sql 语句 alter table 表名+ add column 添加的字段 添加字段的数据类型privatestaticfinalStringALTER_TABLE1="alter table "+TABLE_NAME+" add column test text";publicWTWebViewStatusDB(@NullableContextcontext,@NullableStringname,@NullableSQLiteDatabase.CursorFactoryfactory,intversion){...
shop=# ALTER TABLE Product ALTER COLUMN product_type SET DEFAULT 'other type'; ALTER TABLE shop=# \d Product; Table "public.product" Column | Type | Collation | Nullable | Default ---+---+---+---+--- product_id | character(4) | | not null | product_label | character varying(...
alter table table_name add [constraint constraint_name] type (column); alter table table_name drop constraint constraint_name; 删除表上的主键约束,并删除关联的FOREIGN KEY 约束。 alter table table_name drop primary key cascade; alter table table_name drop primary key | unique(column) | constraint...
如果不想立即为新列指定一个默认值,可以先将新列添加为可为空(NULLABLE),然后更新表中现有行的值,最后再将新列设置为非空。 sql -- 第一步:添加可为空的列 ALTER TABLE table_name ADD COLUMN new_column_name INTEGER; -- 第二步:更新表中现有行的值 UPDATE table_name SET new_column_name = 0 WHE...
自定义表名 @Table(name="xxxPerson")自定义列的属性 @Column(length=10, nullable=false, name="personName") /module1/src/main/java/yuki/jpa/hibernate/app1/module1/bean/person/Person2.txt package yuki.jpa.hibernate.app1.module1.bean;import javax.persistence.Column;import javax.persistence.Entity...
(id integer primary key autoincrement,content text)";publicstaticfinalStringCREATE_MEMBER_AGE="alter table member add column age integer";publicMySQLiteHelper(@NullableContextcontext,@NullableStringname,@NullableSQLiteDatabase.CursorFactoryfactory,intversion){super(context,name,factory,version);}@Override...
Beware that setting it to true may take time for copying table rows. if there are columns in storage that do not exist in db they will be added using 'ALTER TABLE ... ADD COLUMN ...' command and table data will not be dropped but if any of added columns is null but has not ...
SELECT column1, column2...columnN FROM table_name WHERE CONDITION-1 {AND|OR} CONDITION-2; SQLite ALTER TABLE StatementALTER TABLE table_name ADD COLUMN column_def...; SQLite ALTER TABLE Statement (Rename)ALTER TABLE table_name RENAME TO new_table_name; SQLite ATTACH DATABASE StatementATTACH...
Create the column definition for a generated, computed column type. string addModifiers(string $sql, Blueprint $blueprint, Fluent $column) Add the column modifiers to the definition. from Grammar Fluent|null getCommandByName(Blueprint $blueprint, string $name) Get the primary key command ...