Keyword Search On Structured Database

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

2. 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

3. 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

4. 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 ---- 4 ---- or -- 5 color -- and -- doors ---  or -- gears • Based on the Grouping algorithm, we get the following parenthesized query: ( Green and 4 ) or 5

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

6. 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:

7. Example

8. Contd…

9. 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.

10. Data Structure - 2

11. 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:

12. 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., SelectVehicles.color , Vehicles.doors, Vehicles.gears

13. 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.)

14. 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’

15. Conclusion • So Overall, the select statement is: SelectVehicles.color , Vehicles.doors, Vehicles.gears FromVehicles 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.

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