We use the following SQL statement: ALTERTABLEPersons ALTERCOLUMNDateOfBirth year; Notice that the "DateOfBirth" column is now of type year and is going to hold a year in a two- or four-digit format. DROP COLUMN Example Next, we want to delete the column named "DateOfBirth" in the ...
The following ALTER TABLE statement would rename thedepartmentstable todepts: ALTER TABLE departments RENAME TO depts; Practice Exercise #2: Based on theemployeestable below, add a column calledsalarythat is a number(6) datatype. CREATE TABLE employees Solution: The following ALTER TABLE statement ...
SQL ALTER TABLE StatementThe SQL ALTER TABLE command is used to modify the definition (structure) of a table by modifying the definition of its columns. The ALTER command is used to perform the following functions. 1) Add, drop, modify table columns 2) Add and drop constraints 3) ...
The ALTER TABLE statement allows you to rename an existing table. It can also be used to add, modify, or drop a column from an existing table. //z 2012-08-09 09:36:26 IS2120@.T3277072977[T64,L417,R16,V609] Renaming a table The basic syntax for renaming a table is: ALTER TABLE...
Use the ALTER TABLE statement to alter the definition of a nonpartitioned table, a partitioned table, a table partition, or a table subpartition. For object tables or relational tables with object columns, use ALTER TABLE to convert the table to the latest definition of its referenced type ...
For existing rows, the value is that of the SESSION_USER special register at the time the ALTER TABLE statement is processed. CURRENT SQLID Specifies the value of the SQL authorization ID of the process at the time of an SQL data change statement or LOAD, as the default for the column....
For existing rows, the value is that of the SESSION_USER special register at the time the ALTER TABLE statement is processed. CURRENT SQLID Specifies the value of the SQL authorization ID of the process at the time of an SQL data change statement or LOAD, as the default for the column....
ALTER TABLE SQLUser.MyStudents ADD CONSTRAINT UnqFullName UNIQUE (FName,SurName) 可以将多个约束指定为逗号分隔的列表;约束名称应用于第一个约束,其他约束接收默认名称。 约束名称对于表必须是唯一的。为字段指定两次相同的约束名称会生成SQLCODE -400错误:“index name conflict”。
AddAlterFullTextIndexAction AddFileSpec AddMemberAlterRoleAction AddSearchPropertyListAction AddSensitivityClassificationStatement AddSignatureStatement AdHocDataSource AdHocTableReference AffinityKind AlgorithmKeyOption AllowConnectionsOptionKind AlterAction AlterApplicationRoleStatement AlterAssemblyStatement AlterAsymmetric...
AlterTableStatement 类 AlterTableStatement 类 AlterTableStatement 构造函数 AlterTableStatement 方法 AlterTableStatement 属性 AlterTableSwitchStatement 类 AlterTableTriggerModificationStatement 类 AlterTriggerStatement 类 AlterUserStatement 类 AlterViewStatement 类 AlterWorkloadGroupStatement 类 AlterXmlSchemaCollecti...