Αποτελέσματα Αναζήτησης
12 Ιαν 2012 · For MySQL or DBMSes other than MSSQL, you may need to use modify instead of alter for the column value: ALTER TABLE `table name` MODIFY COLUMN `column name` varchar("length"); For MSSQL: ALTER TABLE `table name` ALTER COLUMN `column name` varchar("length");
Use alter table to modify an existing column. You can modify any number of columns in a single alter table statement. For example, this command changes the datatype of the type column in the titles table from char(12) to varchar(20) and makes it nullable:
The ALTER TABLE statement changes table attributes (column definitions and constraints) in a table that was previously created. The syntax allows a list of alter clauses; however, only one table constraint or column constraint can be added, modified, or deleted in each ALTER TABLE statement.
The ALTER TABLE statement changes table attributes (column definitions, constraints, and so on) in an existing table. The database server keeps track of object dependencies in the database. Alterations to the schema of a table may impact dependent views.
Summary: in this tutorial, you will learn how to use the SQL Server ALTER TABLE ALTER COLUMN statement to modify a column of a table. SQL Server allows you to perform the following changes to an existing column of a table: Modify the data type. Change the size. Add a NOT NULL constraint.
Alter table modify column on a huge table containing more than 25 million records. Ask Question. Asked 12 years, 11 months ago. Modified 12 years, 11 months ago. Viewed 5k times. 3. I want to modify a column on a huge table containing more than 25 million records. I am using sybase 12.5.4. I have read through these posts.
I have a table with 45M rows (45 GB data space and 2GB Index space). I added a new column and it finished instantly. alter table T add C char(25) Then I found the size is too small so I run the following query. alter table T alter column C varchar(2500)
