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10 Απρ 2017 · The data type of columns included in an index cannot be changed unless the column is a varchar, nvarchar, or varbinary data type, and the new size is equal to or larger than the old size. Otherwise you would drop the index(es), alter the column, then add back the index(es).
To change the definition of a column in a table, you use the ALTER TABLE MODIFY column syntax as follows: ALTER TABLE table_name MODIFY column_name action ; Code language: SQL (Structured Query Language) ( sql )
To change the data type of a column in a table, use the following syntax: SQL Server / MS Access: ALTER TABLE table_name. ALTER COLUMN column_name datatype; My SQL / Oracle (prior version 10G): ALTER TABLE table_name. MODIFY COLUMN column_name datatype; Oracle 10G and later: ALTER TABLE table_name.
Purpose. 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 after the type has been altered. Note:
12 Νοε 2018 · ALTER TABLE MODIFY column helps to change column datatype to another datatype, set default values, add NULL checks, change scale or size etc
We use ALTER TABLE MODIFY column command to change columns in existing tables. Like increasing or decreasing the width of a column, change the datatype of a column(conditions apply, we will discuss these later on), adding a constraint to a column (conditional), encrypting or decrypting a column etc.
Renaming an existing column to a new name using alter table command. Renaming a column using alter table ALTER TABLE JOBS_Temp RENAME COLUMN COMM TO COMMISSION
