italktocomputers / stringquery

A little query language that transcompiles to SQL. (non-working state)

StringQuery v 0.1

A little query language that transcompiles to SQL. (non-working state)

WARNING: THIS SOFTWARE IS IN ALPHA AND SHOULD NOT BE USED IN PRODUCTION. I HAVE ONLY COMPILED USING GCC ON CENTOS 6.6 & MAC OS X 10.11.2. IF YOU ARE ACCEPTING CODE FROM A URL IT SHOULD BE ENCODED USING THE APPLICATION/X-WWW-FORM-URLENCODED FORMAT. NOT DOING SO CAN LEAD TO COMMAND INJECTION.

To compile using GCC:

gcc main.c parser.c translators/sql.c translators/json.c validation.c extraction.c library.c -lm

To run tests, cd into the /tests directory and run following command:

gcc main.c test_functions.c ../validation.c ../extraction.c ../library.c

Valid statement syntax:

Resource:Type Operator Filter

Resource.Entity specifies the Resource and Entity to apply the filter against.
In a relational database this would be a table and field name.

The following operators are supported:

=
!=
>
<
>=
<=

Filters can be any of the supported types or a collection of types known as a List. Example comparing Entity against a single value:

User.FirstName:String='Andrew'

The following data types are supported:

String
Int8
uInt8
Int16
uInt16
Int24
uInt24
Int32
uInt32
Int64
uInt64
Double
Date
Time
DateTime
@

The last type is a variable which tells the parser you are specifying a Resource.Entity. This data type is used when performing a simple joins.

You can concatenate multiple statements by using one of the following conjunctive operators:

&
|     

If I want to search for multiple names:

User.FirstName:String='Andrew'|User.FirstName:String='Doug'

Which can be shortened by using a List:

User.FirstName:String=('Andrew','Doug')

Each item in a List is separated by a ','. Valid List syntax:

 (value1[,value2,...])

StringQuery supports simple JOINS. Let's say we have the following resources with the following entities:

Person Resource:

Person.Id
Person.FirstName
Person.LastName

Student Resource:

Student.Id
Person.Id
Student.Major

Using the query below, we can join Person and Student on PersonId.

Person.FirstName:String='Andrew'&Person.LastName:String='Schools'&Student.PersonId:@=Person.Id

Exporting to SQL will output:

SELECT
  Person.*
  ,Student.*
FROM Person, Student
WHERE Person.FirstName = 'Andrew'
AND Person.LastName = 'Schools'
AND Student.PersonId = Person.Id

You can also search for NULL values:

Person.Dept:String=NULL

Or by DateTime which uses UTC:

Person.CreatedDate:DateTime=2016-01-01 00:00:00

You can also send a URL encoded string to the parser:

./a.out --code "User.FirstName%3AString%3D%27Andrew%27%26User.Age%3AInt%3D(30%2C31%2C32)" --code-format urlencoded

This allows you to encode a StringQuery string from a URL and safely pass it to the parser without worrying about command injection.

StringQuery supports the following system variables:

__fetch: allows you to specify a list of fields you would like returned.
__order: allows you to specify a list of fields you would like to order by.
__by: allows you to specify a single sort variable: @desc|@asc.

User.FirstName:String='Andrew'&User.LastName:String='Schools'&__fetch:@=(User.FirstName, User.LastName, User.Age)&__order:@=(User.LastName, User.FirstName)&__by:@=desc

Parser Options:

--file          <file>                      Parse code from <file>   
--code          <code>                      Parse code   
--code-format   <urlencoded|nothing>        What format is the code in    Defaults to nothing
--export        <JSON|SQL>                  Export to what format         Defaults to JSON

To Do:

- Make files.
- Parser needs to recognize exit codes from validators.
- Fix SQL and JSON translators
- Enable transcompilation