PostgresField.php

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<?php
 
namespace Wikimedia\Rdbms;
 
class PostgresField implements Field {
    private $name, $tablename, $type, $nullable, $max_length, $deferred, $deferrable, $conname,
        $has_default, $default;
 
    public static function fromText( DatabasePostgres $db, $table, $field ) {
        $q = <<<SQL
SELECT
 attnotnull, attlen, conname AS conname,
 atthasdef,
 pg_get_expr(adbin, adrelid) AS adsrc,
 COALESCE(condeferred, 'f') AS deferred,
 COALESCE(condeferrable, 'f') AS deferrable,
 CASE WHEN typname = 'int2' THEN 'smallint'
  WHEN typname = 'int4' THEN 'integer'
  WHEN typname = 'int8' THEN 'bigint'
  WHEN typname = 'bpchar' THEN 'char'
 ELSE typname END AS typname
FROM pg_class c
JOIN pg_namespace n ON (n.oid = c.relnamespace)
JOIN pg_attribute a ON (a.attrelid = c.oid)
JOIN pg_type t ON (t.oid = a.atttypid)
LEFT JOIN pg_constraint o ON (o.conrelid = c.oid AND a.attnum = ANY(o.conkey) AND o.contype = 'f')
LEFT JOIN pg_attrdef d on c.oid=d.adrelid and a.attnum=d.adnum
WHERE relkind = 'r'
AND nspname=%s
AND relname=%s
AND attname=%s;
SQL;
 
        $table = $db->remappedTableName( $table );
        foreach ( $db->getCoreSchemas() as $schema ) {
            $res = $db->query(
                sprintf( $q,
                    $db->addQuotes( $schema ),
                    $db->addQuotes( $table ),
                    $db->addQuotes( $field )
                )
            );
            $row = $db->fetchObject( $res );
            if ( !$row ) {
                continue;
            }
            $n = new PostgresField;
            $n->type = $row->typname;
            $n->nullable = ( $row->attnotnull == 'f' );
            $n->name = $field;
            $n->tablename = $table;
            $n->max_length = $row->attlen;
            $n->deferrable = ( $row->deferrable == 't' );
            $n->deferred = ( $row->deferred == 't' );
            $n->conname = $row->conname;
            $n->has_default = ( $row->atthasdef === 't' );
            $n->default = $row->adsrc;
 
            return $n;
        }
 
        return null;
    }
 
    public function name() {
        return $this->name;
    }
 
    public function tableName() {
        return $this->tablename;
    }
 
    public function type() {
        return $this->type;
    }
 
    public function isNullable() {
        return $this->nullable;
    }
 
    public function maxLength() {
        return $this->max_length;
    }
 
    public function is_deferrable() {
        return $this->deferrable;
    }
 
    public function is_deferred() {
        return $this->deferred;
    }
 
    public function conname() {
        return $this->conname;
    }
 
    public function defaultValue() {
        if ( $this->has_default ) {
            return $this->default;
        } else {
            return false;
        }
    }
}