Mastering MySQL 4 [Electronic resources] نسخه متنی

Statement Handle Attributes

These attributes apply to statement handles that have been returned from a prepared query. Most of them are read-only and are specific to the statement handle.

CursorName

CursorName (string, read-only)

The name of the cursor associated with the statement handle or undef if it cannot be obtained.

NAME

NAME (array-ref, read-only)

A reference to an array of fieldnames. Names can be uppercase, lowercase, or mixed case. Instead, use NAME_lc or NAME_uc for portability across systems.

For example, to display the second column, use the following:

$sth = $dbh->prepare("select * from customer");
$sth->execute;
@row = $sth->fetchrow_array;
print "Column 2: $sth->{NAME}->[1]";

NAME_hash

NAME_hash (hash-ref, read-only)

Fieldname information returned as reference to a hash. Names can be uppercase, lowercase, or mixed case. The keys of the hash are the fieldnames, and the values are the field index (from 0 for the first field). Instead, use NAME_hash_lc or NAME_hash_uc for portability across systems.

For example:

$sth = $dbh->prepare("select first_name, surname from customer");
$sth->execute;
@row = $sth->fetchrow_array;
print "First name: $row[$sth->{NAME_hash}{first_name}]\n";
print "Surname: $row[$sth->{NAME_hash}{surname}]\n";

NAME_lc

NAME_lc (array-ref, read-only)

The same as NAME but only returns lowercase names.

NAME_lc_hash

NAME_lc_hash (hash-ref, read-only)

The same as NAME_hash but only returns lowercase names.

NAME_uc

NAME_uc (array-ref, read-only)

The same as NAME but only returns lowercase names.

NAME_uc_hash

NAME_uc_hash (hash-ref, read-only)

The same as NAME_hash but only returns uppercase names.

NULLABLE

NULLABLE (array-ref, read-only)

A reference to an array of whether the field can contain nulls. Will contain 0 for no, 1 for yes, and 2 for unknown.

For example:

print "Field 1 can contain a NULL" if $sth->{NULLABLE}->[0];

NUM_OF_FIELDS

NUM_OF_FIELDS (integer, read-only)

The number of fields that the prepared statement will return. It will be 0 for statements that do not return fields (INSERT, UPDATE, and so on).

NUM_OF_PARAMS

NUM_OF_PARAMS (integer, read-only)

The number of placeholders in the prepared statement.

ParamValues

ParamValues (hash ref, read-only)

A reference to a hash containing the values bound to placeholders or undef if not available.

PRECISION

PRECISION (array-ref, read-only)

This is a reference to an array of integers for each field, referring to either the maximum length of the field (nonnumeric fields) or the maximum number of significant digits (not the display size—it excludes the sign, decimal point, E character, and so on).

RowsInCache

RowsInCache (integer, read-only)

The number of unfetched rows in the cache or undef if the driver does not support a local row cache.

SCALE

SCALE (array-ref, read-only)

Returns a reference to an array of integer values for each column. NULL (undef) values indicate columns where scale is not applicable.

Statement

Statement (string, read-only)

The last SQL query passed to the prepare() method.

TYPE

TYPE (array-ref, read-only)

A reference to an array of integer values (representing the data type) for each field.