Dave Rolsky > Alzabo > Alzabo::Index

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NAME ^

Alzabo::Index - Index objects

SYNOPSIS ^

  foreach my $i ($table->indexes)
  {
     foreach my $c ($i->columns)
     {
        print $c->name;
        print '(' . $i->prefix($c) . ')' if $i->prefix($c);
    }
 }

DESCRIPTION ^

This object represents an index on a table. Indexes consist of columns and optional prefixes for each column. The prefix specifies how many characters of the columns should be indexes (the first X chars). Some RDBMS's do not have a concept of index prefixes. Not all column types are likely to allow prefixes though this depends on the RDBMS. The order of the columns is significant.

METHODS ^

columns

Returns an ordered list of the Alzabo::Column objects that are being indexed.

prefix (Alzabo::Column object)

A column prefix is, to the best of my knowledge, a MySQL specific concept, and as such cannot be set when using an RDBMSRules module for a different RDBMS. However, it is important enough for MySQL to have the functionality be present. It allows you to specify that the index should only look at a certain portion of a field (the first N characters). This prefix is required to index any sort of BLOB column in MySQL.

This method returns the prefix for the column in the index. If there is no prefix for this column in the index, then it returns undef.

unique

Returns a boolean value indicating whether the index is a unique index.

fulltext

Returns a boolean value indicating whether the index is a fulltext index.

function

For function indexes, this returns the function being indexed.

id

The id is generated from the table, column and prefix information for the index. This is useful as a canonical name for a hash key, for example.

Returns a string that is the id which uniquely identifies the index in this schema.

table

Returns the Alzabo::Table object to which the index belongs.

AUTHOR ^

Dave Rolsky, <autarch@urth.org>

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