Keyword Search On Structured Database by – Rajvardhan Patil Professor – Dr. Chen 1

Search Engines & Data Format Search Engines: – Unstructured data – Semi Structured data Inability to Search on – Structured / Relational Data – Example: Movie Databases Automobile Database Bank Database 2

Definitions Attributes – The column names of the relational table. Values – The entries (rows) present in the relational table. Example: – Here, – Attributes : car, color, doors, gears – Values: Honda, Red, 4, 5, Toyota, Green, 2 and 4 carcolordoorsgears HondaRed45 ToyotaGreen24 3

Grouping Initially the Query is entered by the user. Consider the following Example: USER Query: find a car having Green color and 4 doors or a car with 5 gears The values and operators are extracted from the query Green -- and or -- 5 color -- and -- doors --- or -- gears Based on the Grouping algorithm, we get the following parenthesized query: ( Green and 4 ) or 5 4

Data Structure - 1 ( Green and 4 ) or 5 5

Step - 1 PART A: Within ROW - combination Now based on the above table, all possible combinations of (Table – Attribute – Value ) for each row is constructed. Here, each entry has a format of: 6

Example 7

Contd… 8

Step - 2 PART B: Across ROW - Combination – Now Based on the result of Part A, the part B is constructed. – For each entry in row m, calculate its combinations with all the entries in row (m+1). Repeat this step recursively, till all the rows are considered. 9

Data Structure

Create Select Statement From the above steps we get all the possible combination of where clause. CONSTRUCTION OF SELECT Statement: – Each row in the above table represents a Select statement. The select statement is constructed from each row as follow: 11

1. Select Clause Consider the following row, as an example: STEP 1: Construct select clause – Consider all the Table.Attribute pairs present in the query and separate them by ‘,’ delimiter. This forms our select clause, as highlighted below. – i.e., Select Vehicles.color, Vehicles.doors, Vehicles.gears 12

2. From Clause STEP 2: Construct from clause Consider all the tables present in the query and separate them by ‘,’ delimiter. This forms our select clause, as highlighted below. – i.e., From Vehicles (Here only one table is added, since ‘Vehicles’ table is repeated thrice, so there is no need to add it multiple times.) 13

3. Where Clause STEP 3: Construct where clause Append all the columns present in the row [ omitting the (-, ~) signs ] so as to form the where clause, as highlighted below: – i.e., Where ( Vehicles.color = ‘Green’ and Vehicles.doors =’4’ ) or Vehicles.gears=’5’ 14

Conclusion So Overall, the select statement is: Select Vehicles.color, Vehicles.doors, Vehicles.gears From Vehicles Where ( Vehicles.color = ‘Green’ and Vehicles.doors =’4’ ) or Vehicles.gears=’5’ Eventually, we transformed the given english statement query into its equivalent SQL statement. 15

Future Work – To implement the set operators, not operator and mathematical operators. Thank You Questions ??? 16