GO4SQL

GO4SQL is an open source project to write in-memory SQL engine using nothing but Golang.

HOW TO USE

You can compile the project with go build, this will create GO4SQL binary.

Currently, there are 3 modes to chose from:

1. File Mode - You can specify file path with ./GO4SQL -file file_path, that will read the input data directly into the program and print the result. In order to run one of e2e test files you can use: shell go build; ./GO4SQL -file e2e/test_files/1_select_with_where_test

2. Stream Mode - With ./GO4SQL -stream you can run the program in stream mode, then you provide SQL commands in your console (from standard input).

3. Socket Mode - To start Socket Server use ./GO4SQL -socket, it will be listening on port 1433 by default. To choose port different other than that, for example equal to 1444, go with: ./GO4SQL -socket -port 1444

UNIT TESTS

To run all the tests locally paste this in root directory:

go clean -testcache; go test ./...

E2E TESTS

There are integrated with Github actions e2e tests that can be found in: .github/workflows/end2end-tests.yml file. Tests run files inside e2e/test_files directory through GO4SQL, save stdout into files, and finally compare then with expected outputs inside e2e/expected_outputs directory.

To run e2e test locally, you can run script ./e2e/e2e_test.sh if you're in the root directory.

Docker

1. Pull docker image: docker pull kajedot/go4sql:latest
2. Run docker container in the interactive mode, remember to provide flag, for example: docker run -i kajedot/go4sql -stream
3. You can test this image with test_file provided in this repo: docker run -i kajedot/go4sql -stream < test_file

SUPPORTED TYPES

• TEXT Type - represents string values. Number or NULL can be converted to this type by wrapping with apostrophes. Columns can store this type with TEXT keyword while using CREATE command.
• NUMERIC Type - represents integer values, columns can store this type with INT keyword while using CREATE command. In general every digit-only value is interpreted as this type.
• NULL Type - columns can't be assigned that type, but it can be used with INSERT INTO, UPDATE, and inside WHERE statements, also it can be a product of JOIN commands (besides FULL JOIN). In GO4SQL NULL is the smallest possible value, what means it can be compared with other types with EQUAL and NOT statements.

FUNCTIONALITY

• CREATE TABLE - you can create table with name table1 using command: sql CREATE TABLE table1( one TEXT , two INT); First column is called one and it contains strings (keyword TEXT), second one is called two and it contains integers (keyword INT).

• DROP TABLE - you can destroy the table of name table1 using command: sql DROP TABLE table1; After using this command table1 will no longer be available and all data connected to it (column definitions and inserted values) will be lost.

• INSERT INTO - you can insert values into table called table1 with command: sql INSERT INTO table1 VALUES( 'hello', 1); Please note that the number of arguments and types of the values must be the same as you declared with CREATE.

• UPDATE - you can update values in table called table1 with command: sql UPDATE table1 SET column_name_1 TO new_value_1, column_name_2 TO new_value_2 WHERE id EQUAL 1; It will update all rows where column id is equal to 1 by replacing value in column_name_1 with new_value_1 and column_name_2 with new_value_2.

• SELECT FROM - you can either select everything from table1 with: SELECT * FROM table1; Or you can specify column names that you're interested in: sql SELECT one, two FROM table1; Note that column names must be the same as you declared with CREATE and also duplicated column names will be ignored.

• WHERE - is used to filter records. It is used to extract only those records that fulfill a specified condition. It can be used with SELECT like this: sql SELECT column1, column2 FROM table_name WHERE column1 NOT 'goodbye' OR column2 EQUAL 3; Supported logical operations are: EQUAL, NOT, OR, AND, FALSE, TRUE.

• IN - is used to check if a value from a column exists in a specified list of values. It can be used with WHERE like this: sql SELECT column1, column2 FROM table_name WHERE column1 IN ('value1', 'value2'); table_name is the name of the table, and WHERE returns rows that value is either equal to value1 or value2

• NOTIN - is used to check if a value from a column doesn't exist in a specified list of values. It can be used with WHERE like this: sql SELECT column1, column2 FROM table_name WHERE column1 NOTIN ('value1', 'value2'); table_name is the name of the table, and WHERE returns rows which values are not equal to value1 and not equal to value2

• DELETE FROM is used to delete existing records in a table. It can be used like this: sql DELETE FROM tb1 WHERE two EQUAL 3; tb1 is the name of the table, and WHERE specify records that fulfill a specified condition and afterward will be deleted.

• ORDER BY is used to sort the result-set in ascending or descending order. It can be used with SELECT like this: sql SELECT column1, column2, FROM table_name ORDER BY column1 ASC, column2 DESC; In this case, this command will order by column1 in ascending order, but if some rows have the same column1, it orders them by column2 in descending order.

• LIMIT is used to reduce number of rows printed out by returning only specified number of records with SELECT like this: sql SELECT column1, column2, FROM table_name ORDER BY column1 ASC LIMIT 5; In this case, this command will order by column1 in ascending order and return 5 first records.

• OFFSET is used to reduce number of rows printed out by not skipping specified numbers of rows in returned output with SELECT like this: sql SELECT column1, column2, FROM table_name ORDER BY column1 ASC LIMIT 5 OFFSET 3; In this case, this command will order by column1 in ascending order and skip 3 first records, then return records from 4th to 8th.

• DISTINCT is used to return only distinct (different) values in returned output with SELECT like this: sql SELECT DISTINCT column1, column2, FROM table_name; In this case, this command will return only unique rows from table_name table.

• INNER JOIN is used to return a new table by combining rows from both tables where there is a match on the specified condition. Only the rows that satisfy the condition from both tables are included in the result. Rows from either table that do not meet the condition are excluded from the result. sql SELECT * FROM tableOne JOIN tableTwo ON tableOne.columnY EQUAL tableTwo.columnX; or sql SELECT * FROM tableOne INNER JOIN tableTwo ON tableOne.columnY EQUAL tableTwo.columnX; In this case, this command will return all columns from tableOne and tableTwo for rows where the condition tableOne.columnY = tableTwo.columnX is met (i.e., the value of columnY in tableOne is equal to the value of columnX in tableTwo).

• LEFT JOIN is used to return a new table that includes all records from the left table and the matched records from the right table. If there is no match, the result will contain empty values for columns from the right table. sql SELECT * FROM tableOne LEFT JOIN tableTwo ON tableOne.columnY EQUAL tableTwo.columnX; In this case, this command will return all columns from tableOne and the matching columns from tableTwo. For rows in tableOne that do not have a corresponding match in tableTwo, the result will include empty values for columns from tableTwo.

• RIGHT JOIN is used to return a new table that includes all records from the right table and the matched records from the left table. If there is no match, the result will contain empty values for columns from the left table. sql SELECT * FROM tableOne RIGHT JOIN tableTwo ON tableOne.columnY EQUAL tableTwo.columnX; In this case, this command will return all columns from tableTwo and the matching columns from tableOne. For rows in tableTwo that do not have a corresponding match in tableOne, the result will include empty values for columns from tableOne.

• FULL JOIN is used to return a new table created by joining two tables as a whole. The joined table contains all records from both tables and fills empty values for missing matches on either side. This join combines the results of both LEFT JOIN and RIGHT JOIN. sql SELECT * FROM tableOne FULL JOIN tableTwo ON tableOne.columnY EQUAL tableTwo.columnX; In this case, this command will return all columns from tableOne and tableTwo for rows fulfilling condition tableOne.columnY EQUAL tableTwo.columnX (value of columnY in tableOne is equal the value of columnX in tableTwo).

• MIN() is used to return the smallest value in a specified column. sql SELECT MIN(columnName) FROM tableName; In this case, this command will return the smallest value found in the column columnName of tableName.

• MAX() is used to return the largest value in a specified column. sql SELECT MAX(columnName) FROM tableName; This command will return the largest value found in the column columnName of tableName.

• COUNT() is used to return the number of rows that match a given condition or the total number of rows in a specified column. sql SELECT COUNT(columnName) FROM tableName; This command will return the number of rows in the columnName of tableName.

• SUM() is used to return the total sum of the values in a specified numerical column. sql SELECT SUM(columnName) FROM tableName; This command will return the total sum of all values in the numerical column columnName of tableName.

• AVG() is used to return the average of values in a specified numerical column. sql SELECT AVG(columnName) FROM tableName; This command will return the average of all values in the numerical column columnName of tableName.

DOCKER

To build your docker image run this command in root directory:

docker build -t go4sql:test .

Run docker in interactive stream mode

To run this docker image in interactive stream mode use this command:

docker run -i go4sql:test -stream

Run docker in socket mode

To run this docker image in socket mode use this command:

docker run go4sql:test -socket

Run docker in file mode

NOT RECOMMENDED

Alternatively you can run a docker image in file mode:

docker run -i go4sql:test -file <PATH_TO_FILE>

HELM

To create a pod deployment using helm chart, there is configuration under ./helm directory.

Commands:

cd ./helm
helm install go4sql_pod_name GO4SQL/

To check status of pod, use:

kubectl get pods