select a.table_name, a.owner, a.constraint_name, a.constraint_type, a.r_owner, a.r_constraint_name,--被外键引用的约束名 b.table_name --被外键引用的表名 from dba_constraints a, dba_constraints b where a.constraint_type = '
select a.table_name, a.owner, a.constraint_name, a.constraint_type, a.r_owner, a.r_constraint_name,--被外键引用的约束名 b.table_name --被外键引用的表名 from dba_constraints a, dba_constraints b where a.constraint_type = 'R' and a.r_constraint_name = b.constraint_name and a.r_...
OceanBase过去的版本中,已在Oracle租户下支持了rename column语法,本次调整是在4.2.1以及往后的版本中,支持MySQL租户的rename column的语法,以兼容MySQL8.0。 2. 功能描述 rename column语法: ALTER TABLE tbl_name [rename_action [, rename_action] ...]; rename_action: RENAME old_col_name To new_col_name...
Alter table 表名 drop constraint 约束名; 1. 检查约束: Alter table 表名 add constraint 约束取名 check(列名和条件 如:salary >2000); 1.
To remove a constraint, use theDROP CONSTRAINTclause in theALTER TABLEstatement. If you wish to drop the unique constraint on the “Email” column: ALTER TABLE Customers DROP CONSTRAINT UQ_Email; 4. Renaming Tables TheALTERcommand allows you to rename a table easily. Suppose you want to ren...
To rename a table, you use the following Oracle RENAME table statement as follows: RENAME table_name TO new_name;Code language: SQL (Structured Query Language) (sql) In the RENAME table statement: First, specify the name of the existing table which you want to rename. Second, provide the...
针对PL/SQL代码（包、函数、过程等），是否存在私有对象的查找⽅法，例如以下：select* from dba_source a where(a.owner, a.name)in (select owner,name from dba_dependencies b where b.referenced_name ='DH_T'and b.referenced_owner ='DBMON')and a.TEXT like'%@%';针对视图中是否存在私有对象的...
11.2.0.2里新增了一个很有意思的新特性——用户重命名(Rename User),以前俺们都是Rename datafile呀,tablespace呀,Index呀,抑或是constraint之类,没想到User也可以重命名的。据说这个DDL操作的需求是来源于SAP: SAP identifies a specific SAP system by the name of the database schema. If the system is rename...
RENAME COLUMN tableName.simpleColumnName TO simpleColumnName Examples To rename the manager column in table employee to supervisor, use the following syntax: RENAME COLUMN EMPLOYEE.MANAGER TO SUPERVISOR You can combine ALTER TABLE and RENAME COLUMN to modify a column's data type. To change column...
In MySQL, the SQL syntax for ALTER TABLE Rename Column is, ALTER TABLE "table_name" Change "column 1" "column 2" ["Data Type"];In Oracle, the syntax is, ALTER TABLE "table_name" RENAME COLUMN "column 1" TO "column 2";Let's look at the example. Assuming our starting point is ...