当尝试将表中的列从varchar(8000)更改为varchar(MAX)时,SSMS会生成一个脚本,该脚本删除表上的约束,创建一个新表,将旧表中的所有数据插入到新表中,删除旧表中的外键,删除旧表,重命名新表这通常比只运行'ALTER TABLE varchar ALTER COLUMN ColumnA varchar(MAX)‘更安全吗?什么时候我想运行SSMS生成的脚本与'ALTER...
shardingAlgorithmName: t_order_inline keyGenerateStrategy: column: order_id keyGeneratorName: snowflake t_order_item: actualDataNodes: ds_${0..1}.t_order_item_${0..1} tableStrategy: standard: shardingColumn: order_id shardingAlgorithmName: t_order_item_inline k...
ALTERTABLE<name>{ALTER|MODIFY}[(][COLUMN]<col1_name>DROPDEFAULT,[COLUMN]<col1_name>SETDEFAULT<seq_name>.NEXTVAL,[COLUMN]<col1_name>{[SET]NOTNULL|DROPNOTNULL},[COLUMN]<col1_name>[[SETDATA]TYPE]<type>,[COLUMN]<col1_name>COMMENT'<string>',[COLUMN]<col1_name>UNSETCOMMENT[,[COLUMN]<c...
PostgreSQL Redshift MySQL SQL Server BigQuery SnowflakePostgreSQL: Change a Column Name Here's an example of renaming a column in PostgreSQL: alter table users rename column registered_at to created_at; Previous How to Add a Default Value NextHow to Add a Column ...