different structures and objects in a database. DDL statements create, modify and remove database objects, such as tables, indexes and stogroups. DDL is also used in a generic sense to refer to any language that describes data.
DDL (Data Define Language) 数据定义语言:常用的有CREATE和DROP,用于在数据库中创建新表或删除表,以及为表加入索引等 DCL(Data Control Language) 数据控制语言:通过GRANT和REVOKE,确定单个用户或用户组对数据库对象的访问权限 hiveDDL操作 hive数据类型 hive数据编码 hive数据类型转换 hive创建数据库 hive创建表(...
data_type,有两种类型:一种是复杂类型,例如array_type(ARRAY < data_type >)、map_type(MAP < primitive_type, data_type >)、struct_type(STRUCT < col_name : data_type [COMMENT col_comment], ...>)、union_type(UNIONTYPE < data_type, data_type, ... >);简单类型有SMALLINT(占2个字节的整...
DROP(DATABASE|SCHEMA) [IFEXISTS] database_name [RESTRICT|CASCADE];--默认RESTRICT:数据库不为空将失败;CASCADE:强制全部删除 Alter Database --修改参数ALTER(DATABASE|SCHEMA) database_nameSETDBPROPERTIES (property_name=property_value, ...);--修改所有者ALTER(DATABASE|SCHEMA) database_nameSETOWNER [...
Data definition language (DDL) is used to define or modify an object in a database, such as a table, index, or view.GaussDB(DWS) does not support DDL if its CN is unavail
/user/hadoop/hive/warehouse/[databasename.db]/table 4.Bucket(桶):暂且不讲 DDL操作(Data Definition Language) 参考官方文档:DDL文档 HiveQL DDL statements are documented here, including: CREATE DATABASE/SCHEMA, TABLE, VIEW, FUNCTION, INDEX
DDL(Data Definition Language)数据定义语句。这些语句定义了不同的数据段、数据库、表、列、索引、约束等数据库对象。常用的语句关键字主要有CREATGE、DROP、ALTER等。是对数据库内部对象进行创建、删除、修改等操作的语言。 数据库 创建数据库 CREATE DATAB ... 数据库 MySQL mysql 字段 删除表 转载 mb5fe94...
/user/hadoop/hive/warehouse/[databasename.db]/table 4.Bucket(桶):暂且不讲DDL操作(Data Definition Language)参考官方文档:DDL文档HiveQL DDL statements are documented here, including:CREATE DATABASE/SCHEMA, TABLE, VIEW, FUNCTION, INDEX DROP DATABASE/SCHEMA, TABLE, VIEW, INDEX TRUNCATE TABLE ALTER ...
It is same as “DELETE FROM <table_name>” except Truncate does not generate any rollback data hence, it cannot be roll backed. If any delete triggers are defined on the table. Then the triggers are not fired It deallocates free extents from the table. So that the free space can ...
DatabaseExists- checks if the database that is specified as the database in the current connection string exists on the data source. CreateDDLScript- generates a data definition language (DDL) script that creates schema objects (tables, primary keys, foreign keys) by using the metadata provided...