Updating column name in sql

22-Sep-2015 22:50 by 5 Comments

Updating column name in sql - Oh freesex bhutan

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Back in the early days of Oracle7 it was a very cumbersome procedure to rename a column within a table, and some brave DBA's would go into the data dictionary and re-name the column directly!

Internally, the rename column syntax adjusts the Oracle data dictionary only, since the column names are not stored directly inside the segment itself: desc sales Name Null?

Type ---------------- -------- --------------- STORE_KEY VARCHAR2(4) BOOK_KEY VARCHAR2(6) ORDER_NUMBER VARCHAR2(20) ORDER_DATE DATE desc sales Name Null?

The maximum table name length is 127 characters; longer names are truncated to 127 characters.

You cannot rename a permanent table to a name that begins with '#'.

A table name beginning with '#' indicates a temporary table.

Adds a column with the specified name to the table.

You can add only one column in each ALTER TABLE statement.

You cannot add a column that is the distribution key (DISTKEY) or a sort key (SORTKEY) of the table.

You cannot use an ALTER TABLE ADD COLUMN command to modify the following table and column attributes: The data type of the column being added.

For CHAR and VARCHAR columns, you can use the MAX keyword instead of declaring a maximum length.

MAX sets the maximum length to 4096 bytes for CHAR or 65535 bytes for VARCHAR.