关于informix脚本更改主键问题

[underhiswing]

#!/bin/sh
#################################################
#功能: informix 修改数据库主键
#################################################

chg_primary_key()
{
if [ $# -ne 2 ];then
echo "<ERROR> Uargs: chg_primary_key tableName primaryKey /n[$*]"
exit 1
fi

_tableName="$1"
_primaryKey="$2"

alias dbaccess='dbaccess'

#查出老的主键约束名
_constrName=`dbaccess remotedb 2>> tmp.txt << EOF | xargs | cut -d ' ' -f2
select constrname from sysconstraints where constrtype='P'
and tabid= ( select tabid from systables where tabname = '$_tableName' ) ;
EOF `

if [ -z "$_constrName" ] || [ "$_constrName" = "constrname" ];then
echo "<ERROR>主键名查出为空!"
exit 1
fi

#修改主键
dbaccess remotedb << EOF
alter table $_tableName drop constraint $_constrName;
alter table $_tableName add constraint
primary key ($_primaryKey) constraint $_constrName;
EOF

}

#debitrec修改主键为(policyno,classcode,loandate)
chg_primary_key debitrec policyno,classcode,loandate

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以上的脚本能用么？使用什么命令执行？能用的话是 *.sh 文件还是其他类型的文件。如果有知道的请说详细些！感激不尽！

[underhiswing]

各位大神，求教