SQLite教程笔记(一)SQLite命令DDL -- 数据定义语言DML -- 数据操作语言DQL -- 数据查询语言SQLite语法SQLite语句ANALYZE语句AND/OR子句ALTER TABLE语句ATTACH DATABASE语句BEGIN TRANSACTION语句BETWEEN子句COMMIT语句CREATE INDEX语句CREATE TABLE语句CREATE TRIGG sqlite学习 python SQL 数据库 数据 sqlite教程 sqlite学习 ...
CREATE INDEX idx_your_column ON your_table(your_column); CREATE INDEX idx_composite ON your_table(column1, column2); 调整查询语句以减少不必要的数据处理: 避免使用SELECT *,只选择需要的列。 优化WHERE子句,避免使用OR连接多个条件(除非能利用索引)。 使用IN代替多个OR条件。 对于LIKE查询,尽量避免使...
你可以启用@Index和 @CompositeIndex这两个注解,方法是: Cupboardcupboard=newCupboardBuilder().useAnnotations().build(); 这两个注解的相关介绍见:https://bitbucket.org/qbusict/cupboard/wiki/existingData 如何定义某一列的数据类型(int或text)? Cupboard 会自动判断所需的数据类型吗?
CREATE INDEX i2 ON parent(e); CREATE UNIQUE INDEX i3 ON parent(f COLLATE nocase); CREATE TABLE child1(f, g REFERENCES parent(a)); -- Ok CREATE TABLE child2(h, i REFERENCES parent(b)); -- Ok CREATE TABLE child3(j, k, FOREIGN KEY(j, k) REFERENCES parent(c, d)); -- Ok C...
MigrationTo49.createMsgCompositeIndex(db);case49: MigrationTo50.foldersAddNotifyClassColumn(db, migrationsHelper);case50: MigrationTo51.db51MigrateMessageFormat(db, migrationsHelper);case51: MigrationTo52.addMoreMessagesColumnToFoldersTable(db);case52: ...
Optionally, aPRIMARY KEYfor the table. Both single column and composite (multiple column) primary keys are supported. A set of SQLconstraintsfor each table. SQLite supports UNIQUE, NOT NULL, CHECK and FOREIGN KEY constraints. A unique indexes will automatically create to enforce a UNIQUE or PRIM...
Sequence:排列。存储物理地址Index:索引。依附于表,为提高检索速度。 View:视图。看到表的一部分数据。 限制数据访问。简化查询。数据独立性。本质上是一个sql查询语句。 Create[or Relace][Force|noForce] View 视图名 [(alias[,alias]…)] 别名列表
createIndex() Builds a SQL statement for creating a new index. yii\db\sqlite\QueryBuilder createTable() Builds a SQL statement for creating a new DB table. yii\db\QueryBuilder createView() Creates a SQL View. yii\db\QueryBuilder delete() Creates a DELETE SQL statement. yii\db\QueryBuilde...
@CompositeIndex(colums = { "name", "phone" }, unique = true) public class User extends BaseModel { Integer type; // 类型 0客户 1经销商 String name; @SingleIndex(unique = true) String phone; public String getPhone() { return phone; ...
You can have a composite primary key in SQLite, but you have to create the key when you create the table: CREATE TABLE example1( field1 FLOAT, field2 TEXT, PRIMARY KEY(field1, field2) ); You cannot create the primary key after the fact using ALTER TABLE. ...