Difference between revisions of "PRIMARY KEY Table Constraint"
Helengeorge (Talk | contribs) |
Helengeorge (Talk | contribs) (→Products) |
||
| Line 29: | Line 29: | ||
==Products== | ==Products== | ||
| − | Recital | + | Recital, Recital Server |
[[Category:Documentation]] | [[Category:Documentation]] | ||
[[Category:SQL]] | [[Category:SQL]] | ||
Revision as of 17:18, 8 December 2009
Purpose
Table constraint to define table's Primary Key
Syntax
PRIMARY KEY <expr> TAG <cTagName> [COLLATE <cCollateSequence>]
See Also
ALTER TABLE, CONSTRAINTS, CREATE TABLE
Description
A constraint is used to define rules that help to provide data integrity. TABLE constraints apply to table-based operations. You must have ALTER privilege on the table. The table will be locked for EXCLUSIVE use during the operation.
The PRIMARY KEY table constraint is used to define <expr> as the table's Primary Key. The <expr> can contain any valid index key. A unique tag index is built on the specified <expr>; it is given the name as defined in <cTagName>. If a table already has a primary key defined, an error will be returned.
The optional COLLATE <cCollateSequence> clause is included for Visual FoxPro language compatibility only.
Example
set sql to vfp CREATE TABLE newcust (acc_ref char(5) default strzero(seqno(),5), acc_name char(20)) ALTER TABLE newcust ADD PRIMARY KEY acc_ref+acc_name TAG RefName list structure index
Products
Recital, Recital Server
