hello everybody,
I have a table with 3lakhs records but unfortunately the table does not have a primary key defined, how can I make the querying of the table faster, if my query contains a where clause like say 'where invno like '%parameter%';.

STRUCTURE OF THE TABLE IS AS FOLLOWS:
LOCNID NOT NULL VARCHAR2(6) => foreign key
DOCNO NOT NULL VARCHAR2(8)
DOCDT NOT NULL DATE
DOCID NOT NULL VARCHAR2(14)
VCH_TYPE NOT NULL VARCHAR2(2)
SRNO NUMBER(4)
ACT_CODE NOT NULL VARCHAR2(9) => foreign key
PARTICULARS VARCHAR2(100)
DRAWEE_BANK VARCHAR2(30)
CHEQNO VARCHAR2(15)
CHEQDT DATE
INVNO VARCHAR2(10)
INVDT DATE
CSTCD VARCHAR2(8)
ANLYCD VARCHAR2(4)
GLEDG_DR_AMT NUMBER(12,3)
GLEDG_CR_AMT NUMBER(12,3)
GLEDG_BALANCE_AMT NUMBER(12,3)
PENDING_UPDATED_FLAG VARCHAR2(1)
STATUS VARCHAR2(1)