talentaa / dbms Goto Github PK

IMPORTANT!

1. Read the design documents.
2. First of all, take a look at queryExamples.txt
3. Do make (the Makefile of the system is in the package). Then
4. Do mkdir ./config : The program requires that there be a config directory in the base directory. The metadata file is to be stored there;
5. Do touch ./dataspace.rdb : There must be dataspace.rdb file in the base directory. All the data will be found in this file, but the program will fail if this file does not exist. The first time the program is run, this file should be empty;
6. Do "chmod 755 (or 700 or any code that gives RWE permissions to the owner of the "dbms".

==> Now you can run the main program dbms.

We define an interface function so that a third party application can make use of our database system.

Prototype:

extern char* result;

int sql(char* query);

    char* query: any SQL query or a DBA command

Return values:

• Returns 0, if successful.
• Otherwise, returns negative integers depending on the error-causing functions.

Implementation:

We define a global variable (a character array) in the library that holds the results of the query.

The application can access the global variable via "extern char* result".

For the table-manipulation functions such as SELECT or INSERT, the result will be stored in the global variable. For other house-keeping functions such as OPEN DB, the result will be returned through the return value of the sql function.

In order to store the results from the table operations, display_table() function should be modified in such a way that all the "cout" or "printf" calls are followed by memcpy or sprintf function calls so that the results should also get copied into the global variable.

It can be found in queryExamples.txt.