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diff --git a/doc/man/alter_table.l b/doc/man/alter_table.l new file mode 100644 index 00000000000..245533a03c4 --- /dev/null +++ b/doc/man/alter_table.l @@ -0,0 +1,61 @@ +.\" This is -*-nroff-*- +.\" XXX standard disclaimer belongs here.... +.\" $Header: /cvsroot/pgsql/doc/man/Attic/alter_table.l,v 1.1.1.1 1996/08/18 22:14:19 scrappy Exp $ +.TH "ALTER TABLE" SQL 11/5/95 Postgres95 Postgres95 +.SH NAME +alter table \(em add attributes to a class +.SH SYNOPSIS +.nf +\fBalter table\fR classname [*] + \fBadd column\fR attname type + +.fi +.SH DESCRIPTION +The +.BR "alter table" +command +causes a new attribute to be added to an existing class, +.IR classname . +The new attributes and their types are specified +in the same style and with the the same restrictions as in +.IR create table (l). +.PP +In order to add an attribute to each class in an entire inheritance +hierarchy, use the +.IR classname +of the superclass and append a \*(lq*\*(rq. (By default, the +attribute will not be added to any of the subclasses.) This should +.BR always +be done when adding an attribute to a superclass. If it is not, +queries on the inheritance hierarchy such as +.nf +select * from super* s +.fi +will not work because the subclasses will be missing an attribute +found in the superclass. +.PP +For efficiency reasons, default values for added attributes are not +placed in existing instances of a class. That is, existing instances +will have NULL values in the new attributes. If non-NULL values are +desired, a subsequent +.IR update (l) +query should be run. +.PP +You must own the class in order to change its schema. +.SH EXAMPLE +.nf +-- +-- add the date of hire to the emp class +-- +alter table emp add column hiredate abstime +.fi +.nf +-- +-- add a health-care number to all persons +-- (including employees, students, ...) +-- +alter table person * add column health_care_id int4 +.fi +.SH "SEE ALSO" +create table (l), +update (l). |