Convert MySQL schema to Github Wiki?

Question

I am documenting a project using GitHub Wiki pages, and now I would like to export the MySQL database schema into markdown format. Is there a way to convert the CLI output to GitHub Wiki md? Ideally as tables.

My output looks like this:

Answer 1

This code is rather long. I apologize. It consists of two stored procedures. You may be satisfied running just the first one. The second uses the output from the first (the data the first left in tables). You may also wish to combine the code into one. But I kept them separate. The second stored proc produces the output to resemble describe myTable. But it performs it for ALL tables in the database you desire such output.

You use this by passing a parameter (string) for the database to report on.

I create a separate database, and the code explicitly references tables in that database by name. So if you have EXECUTE privileges to this stored procedure, you can run it from any current database. So, as a simple test, do not set the reporting database as your current database, and merely call the stored procedure by name (qualified with reporting db name). This is all shown in the Test chunk below.

Two Stored Procedures

CREATE SCHEMA Reporting101a;    -- See **Note1**

DROP PROCEDURE IF EXISTS `Reporting101a`.`describeTables_v2a`;
DELIMITER $$
CREATE DEFINER=`root`@`localhost` PROCEDURE `Reporting101a`.`describeTables_v2a`(
    IN dbName varchar(100), -- the dbname to report table structures
    OUT theSession int, -- OUT parameter for session# assigned
    IN deleteSessionRows BOOL, -- true for delete rows when done from main reporting table for this session#
    IN callTheSecondStoredProc BOOL -- TRUE = output is from Pretty output in Second Stored Proc. FALSE= not so pretty output
)
BEGIN
    DECLARE thisTable CHAR(100);

    DROP TEMPORARY TABLE IF EXISTS Reporting101a.tOutput;
    CREATE TEMPORARY TABLE Reporting101a.tOutput
    (   id int auto_increment primary key,
        tblName varchar(100) not null,
        ordVal int not null,
        cField varchar(100) not null,
        cType varchar(100) not null,
        cNull varchar(100) not null,
        cKey varchar(100) not null,
        cDefault varchar(100) null,
        cExtra varchar(100) null
    );
    DROP TEMPORARY TABLE IF EXISTS Reporting101a.tOutput2;
    CREATE TEMPORARY TABLE Reporting101a.tOutput2
    (   tblName varchar(100) primary key,
        colCount int not null,
        cFieldMaxLen int not null,
        cTypeMaxLen int not null,
        cNullMaxLen int not null,
        cKeyMaxLen int not null,
        cDefaultMaxLen int not null,
        cExtraMaxLen int not null
    );

    INSERT Reporting101a.tOutput(tblName,ordVal,cField,cType,cNull,cKey,cDefault,cExtra)
    SELECT TABLE_NAME,ORDINAL_POSITION,COLUMN_NAME AS Field, COLUMN_TYPE AS TYPE, RPAD(IS_NULLABLE,4,' ') AS 'Null', 
    RPAD(COLUMN_KEY,3,' ') AS 'Key',RPAD(COLUMN_DEFAULT,7,' ') AS 'DEFAULT',EXTRA AS Extra
    FROM information_schema.columns WHERE table_schema = dbName ORDER BY table_name,ordinal_position; 
    -- select * from information_schema.columns WHERE table_schema = '57security' order by table_name,ordinal_position; 

    UPDATE Reporting101a.tOutput
    SET cExtra='     '
    WHERE cExtra='';

    UPDATE Reporting101a.tOutput
    SET cField=RPAD(cField,5,' ')
    WHERE LENGTH(cField)<5;

    INSERT Reporting101a.tOutput2(tblName,colCount,cFieldMaxLen,cTypeMaxLen,cNullMaxLen,cKeyMaxLen,cDefaultMaxLen,cExtraMaxLen)
    SELECT tblName,COUNT(*),0,0,0,0,0,0 
    FROM Reporting101a.tOutput 
    GROUP BY tblName;

    UPDATE tOutput2 t2
    JOIN
    (   SELECT tblName,MAX(LENGTH(cField)) AS mField,MAX(LENGTH(cType)) AS mType,MAX(LENGTH(cNull)) AS mNull,
        IFNULL(MAX(LENGTH(cKey)),0) AS mKey,IFNULL(MAX(LENGTH(cDefault)),0) AS mDefault,IFNULL(MAX(LENGTH(cExtra)),0) AS mExtra
        FROM Reporting101a.tOutput
        GROUP BY tblName
    ) x
    ON x.tblName=t2.tblName
    SET t2.cFieldMaxLen=x.mField,t2.cTypeMaxLen=x.mType,cNullMaxLen=x.mNull,
    cKeyMaxLen=x.mKey,cDefaultMaxLen=x.mDefault,cExtraMaxLen=x.mExtra;

    -- DROP TABLE Reporting101a.reportDataDefsSession; -- useful for quick change of structure of table
    -- note, keep above drop call remmed out ! Just use it for quick tweaks to structure
    CREATE TABLE IF NOT EXISTS Reporting101a.reportDataDefsSession
    (   -- for the sole purpose of safe session auto_inc usage
        -- Please don't delete unless you want the sessions to experience aberant behavior
        sessionId INT AUTO_INCREMENT PRIMARY KEY,
        dummy CHAR(1) NOT NULL,
        creationDT datetime not null
    );

    CREATE TABLE IF NOT EXISTS Reporting101a.reportDataDefs
    (   sessionId INT NOT NULL,
        tblName VARCHAR(100) NOT NULL,  -- Tablename
        ordVal INT NOT NULL,    -- the "position number" of the Column
        cField VARCHAR(100) NOT NULL,   -- The Column
        cType VARCHAR(100) NOT NULL,    -- Datatype
        cNull VARCHAR(100) NOT NULL,    -- Nullability
        cKey VARCHAR(100) NOT NULL, -- Key info
        cDefault VARCHAR(100) NULL, -- Default value
        cExtra VARCHAR(100) NULL,   -- Extra output
        colCount INT NOT NULL,  -- the columns here and below are de-normalize data
        cFieldMaxLen INT NOT NULL,
        cTypeMaxLen INT NOT NULL,
        cNullMaxLen INT NOT NULL,
        cKeyMaxLen INT NOT NULL,
        cDefaultMaxLen INT NOT NULL,
        cExtraMaxLen INT NOT NULL
    );

    -- For lack of a better notion, we are calling calls "sessions". The programmer calls the
    -- First Stored Proc, and we call that a session after we get a unique next incrementing number.
    -- That number is the session #. House all output with that as a column value. This allows us to 
    -- move between stored procs, have safe output, have historical snapshots, and retain the data 
    -- via a session # for later use, whatever use.
    INSERT Reporting101a.reportDataDefsSession(dummy,creationDT) VALUES ('X',now());
    SET @mySession=LAST_INSERT_ID(); -- there it is, our session # (read the above paragraph)

    INSERT Reporting101a.reportDataDefs(sessionId,tblName,ordVal,cField,cType,cNull,cKey,cDefault,cExtra,
    colCount,cFieldMaxLen,cTypeMaxLen,cNullMaxLen,cKeyMaxLen,cDefaultMaxLen,cExtraMaxLen)    
    SELECT @mySession,t1.tblName,t1.ordVal,t1.cField,t1.cType,t1.cNull,t1.cKey,t1.cDefault,t1.cExtra,
    t2.colCount,t2.cFieldMaxLen,t2.cTypeMaxLen,t2.cNullMaxLen,t2.cKeyMaxLen,t2.cDefaultMaxLen,t2.cExtraMaxLen 
    FROM Reporting101a.tOutput t1
    JOIN Reporting101a.tOutput2 t2
    ON t2.tblName=t1.tblName
    ORDER BY t1.tblName,t1.id;

    DROP TEMPORARY TABLE Reporting101a.tOutput;
    DROP TEMPORARY TABLE Reporting101a.tOutput2;
    SET theSession=@mySession; -- the OUT var that came in as a parameter

    -- ***************************************************************************
    -- ***************************************************************************
    -- Label "Some_Sort_of_Output":
    IF callTheSecondStoredProc=TRUE THEN
        -- The caller says to call the second stored proc (for Pretty Printing)
        -- This will generate output similar to `DESCRIBE myTable`
        -- But remember, it will do it  for EVERY table in referenced database
        CALL Reporting101a.`Print_Tables_Like_Describe`(@mySession);
        -- The above call just gave you output.
    ELSE
        -- The caller chose to not auto call the Pretty Printing second stored procedure.
        -- Note, the caller can easily call it right after using the OUT parameter.
        -- So our output will be a resultset of out reportDataDefs table for this session #
        SELECT * 
        FROM Reporting101a.reportDataDefs 
        WHERE sessionId=@mySession
        ORDER BY tblName,ordVal;
    END IF;
    -- ***************************************************************************
    -- ***************************************************************************

    IF deleteSessionRows=TRUE THEN
        -- The caller says output rows are NOT needed at this point. Delete them.
        -- Note, if this boolean comes in TRUE, you can't call Pretty Printing
        -- second stored procedure with the session # because the data is gone.
        --
        -- Regardless, you are getting something back from "Some_Sort_of_Output" above.
        DELETE FROM Reporting101a.reportDataDefs
        WHERE sessionId=@mySession;
    END IF;
END$$
DELIMITER ;

DROP PROCEDURE IF EXISTS `Reporting101a`.`Print_Tables_Like_Describe`;
DELIMITER $$
CREATE DEFINER=`root`@`localhost` PROCEDURE `Reporting101a`.`Print_Tables_Like_Describe`(
    pSessionId INT
)
BEGIN
    DECLARE done INT DEFAULT FALSE;
    DECLARE curTable VARCHAR(100) DEFAULT '';
    DECLARE bFirst BOOL DEFAULT TRUE;

    DECLARE lv_tblName,lv_cField,lv_cType,lv_cNull,lv_cKey,lv_cDefault,lv_cExtra VARCHAR(100);
    DECLARE lv_ordVal,lv_colCount,lv_cFieldMaxLen,lv_cTypeMaxLen,lv_cNullMaxLen,lv_cKeyMaxLen,lv_cDefaultMaxLen,lv_cExtraMaxLen INT;

    DECLARE cur1 CURSOR FOR SELECT tblName,ordVal,cField,cType,cNull,cKey,cDefault,cExtra,
    colCount,cFieldMaxLen,cTypeMaxLen,cNullMaxLen,cKeyMaxLen,cDefaultMaxLen,cExtraMaxLen 
    FROM Reporting101a.reportDataDefs
    WHERE sessionId=pSessionId
    ORDER BY tblName,ordVal;

    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

    -- Please note in the above, CURSOR stuff must come last else "Error 1337: Variable or condition decl aft curs" 

    CREATE TABLE IF NOT EXISTS Reporting101a.reportOutput
    (   lineNum INT AUTO_INCREMENT PRIMARY KEY,
        sessionId INT NOT NULL,
        lineOut varchar(100) NOT NULL
    );

    -- INSERT Reporting101a.reportOutput(sessionId,lineOut)
    -- SELECT 
    -- SET curTable='';
    DELETE FROM Reporting101a.reportOutput
    WHERE sessionId=pSessionId;

    OPEN cur1;

    read_loop: LOOP
        FETCH cur1 INTO lv_tblName,lv_ordVal,lv_cField,lv_cType,lv_cNull,lv_cKey,lv_cDefault,lv_cExtra,
            lv_colCount,lv_cFieldMaxLen,lv_cTypeMaxLen,lv_cNullMaxLen,lv_cKeyMaxLen,lv_cDefaultMaxLen,lv_cExtraMaxLen ;
        IF done THEN
            LEAVE read_loop;
        END IF;
        IF lv_tblName<>curTable THEN
            IF bFirst=FALSE THEN
                INSERT Reporting101a.reportOutput(sessionId,lineOut)
                SELECT pSessionId,'';
            ELSE
                SET bFirst=FALSE;
            END IF;
            INSERT Reporting101a.reportOutput(sessionId,lineOut)
            SELECT pSessionId,lv_tblName;
            INSERT Reporting101a.reportOutput(sessionId,lineOut)
            SELECT pSessionId,CONCAT('+-', 
                REPEAT('-',GREATEST(5,lv_cFieldMaxLen)),  '-+-',
                REPEAT('-',GREATEST(4,lv_cTypeMaxLen)), '-+-',
                REPEAT('-',GREATEST(4,lv_cNullMaxLen)), '-+-',
                REPEAT('-',GREATEST(3,lv_cKeyMaxLen)),  '-+-',
                REPEAT('-',GREATEST(7,lv_cDefaultMaxLen)),  '-+-',
                REPEAT('-',GREATEST(5,lv_cExtraMaxLen)),    '-+');

            SET @dashLineNumRow=LAST_INSERT_ID();

            INSERT Reporting101a.reportOutput(sessionId,lineOut)
            SELECT pSessionId,CONCAT('| ', 
                'Field',
                REPEAT(' ',GREATEST(0,lv_cFieldMaxLen-5)),  ' | ',
                'Type',
                REPEAT(' ',GREATEST(0,lv_cTypeMaxLen-4)),   ' | ',
                'Null',
                REPEAT(' ',GREATEST(0,lv_cNullMaxLen-4)),   ' | ',
                'Key',
                REPEAT(' ',GREATEST(0,lv_cKeyMaxLen-3)),    ' | ',
                'Default',
                REPEAT(' ',GREATEST(0,lv_cDefaultMaxLen-7)),    ' | ',
                'Extra',
                REPEAT(' ',GREATEST(0,lv_cExtraMaxLen-5)),  ' |');

            INSERT Reporting101a.reportOutput(sessionId,lineOut)
            SELECT pSessionId,lineOut
            FROM Reporting101a.reportOutput
            WHERE lineNum=@dashLineNumRow;

            -- SELECT * FROM Reporting101a.reportDataDefs WHERE sessionId=24;
            SET curTable=lv_tblName;
        END IF;
        INSERT Reporting101a.reportOutput(sessionId,lineOut)
        SELECT pSessionId,
            CONCAT('| ', 
            COALESCE(lv_cField,''),
            COALESCE(REPEAT(' ',GREATEST(0,lv_cFieldMaxLen-LENGTH(lv_cField))),''),' | ',
            COALESCE(lv_cType,''),
            COALESCE(REPEAT(' ',GREATEST(0,lv_cTypeMaxLen-LENGTH(lv_cType))),''),' | ',
            COALESCE(lv_cNull,''),
            COALESCE(REPEAT(' ',GREATEST(0,lv_cNullMaxLen-LENGTH(lv_cNull))),''),' | ',
            COALESCE(lv_cKey,'   '),
            COALESCE(REPEAT(' ',GREATEST(0,lv_cKeyMaxLen-LENGTH(lv_cKey))),''),' | ',
            COALESCE(lv_cDefault,'       '),
            COALESCE(REPEAT(' ',GREATEST(0,lv_cDefaultMaxLen-LENGTH(lv_cDefault))),''),' | ',
            COALESCE(lv_cExtra,'     '),
            COALESCE(REPEAT(' ',GREATEST(0,lv_cExtraMaxLen-LENGTH(lv_cExtra))),''),' |');
        INSERT Reporting101a.reportOutput(sessionId,lineOut)
        SELECT pSessionId,lineOut
        FROM Reporting101a.reportOutput
        WHERE lineNum=@dashLineNumRow;
    END LOOP;
    CLOSE cur1;

    select lineOut as '' from Reporting101a.reportOutput where sessionId=pSessionId order by lineNum;
END$$
DELIMITER ;

Test

Test:

-- See **Note2**
SET @theOutVar =-1; -- A variable used as the OUT variable below

-- See **Note3**
-- Note: with `TRUE` as the 4th parameter, this is a one call deal. Meaning, you are done.
call Reporting101a.describeTables_v2a('stackoverflow',@theOutVar,false,true);

-- See **Note4**
-- Primarily used if the 4th parameter above is false
call Reporting101a.Print_Tables_Like_Describe(@theOutVar); -- loads data for prettier results in chunk format.

Output

+--------------------------------------------------------------------------------------------+
|                                                                                    |
+--------------------------------------------------------------------------------------------+
| course                                                                                     |
| +------------+--------------+------+-----+---------+----------------+                      |
| | Field      | Type         | Null | Key | Default | Extra          |                      |
| +------------+--------------+------+-----+---------+----------------+                      |
| | courseId   | int(11)      | NO   | PRI |         | auto_increment |                      |
| +------------+--------------+------+-----+---------+----------------+                      |
| | deptId     | int(11)      | NO   | MUL |         |                |                      |
| +------------+--------------+------+-----+---------+----------------+                      |
| | courseName | varchar(100) | NO   |     |         |                |                      |
| +------------+--------------+------+-----+---------+----------------+                      |
|                                                                                            |
| dept                                                                                       |
| +----------+--------------+------+-----+---------+----------------+                        |
| | Field    | Type         | Null | Key | Default | Extra          |                        |
| +----------+--------------+------+-----+---------+----------------+                        |
| | deptId   | int(11)      | NO   | PRI |         | auto_increment |                        |
| +----------+--------------+------+-----+---------+----------------+                        |
| | deptName | varchar(100) | NO   |     |         |                |                        |
| +----------+--------------+------+-----+---------+----------------+                        |
|                                                                                            |
| scjunction                                                                                 |
| +------------+---------+------+-----+---------+----------------+                           |
| | Field      | Type    | Null | Key | Default | Extra          |                           |
| +------------+---------+------+-----+---------+----------------+                           |
| | id         | int(11) | NO   | PRI |         | auto_increment |                           |
| +------------+---------+------+-----+---------+----------------+                           |
| | studentId  | int(11) | NO   | MUL |         |                |                           |
| +------------+---------+------+-----+---------+----------------+                           |
| | courseId   | int(11) | NO   | MUL |         |                |                           |
| +------------+---------+------+-----+---------+----------------+                           |
| | term       | int(11) | NO   |     |         |                |                           |
| +------------+---------+------+-----+---------+----------------+                           |
| | attendance | int(11) | NO   |     |         |                |                           |
| +------------+---------+------+-----+---------+----------------+                           |
| | grade      | int(11) | NO   |     |         |                |                           |
| +------------+---------+------+-----+---------+----------------+                           |
|                                                                                            |
| student                                                                                    |
| +-----------+--------------+------+-----+---------+----------------+                       |
| | Field     | Type         | Null | Key | Default | Extra          |                       |
| +-----------+--------------+------+-----+---------+----------------+                       |
| | studentId | int(11)      | NO   | PRI |         | auto_increment |                       |
| +-----------+--------------+------+-----+---------+----------------+                       |
| | fullName  | varchar(100) | NO   |     |         |                |                       |
| +-----------+--------------+------+-----+---------+----------------+                       |
|                                                                                            |
| testtable                                                                                  |
| +-----------------------------------------+---------------+------+-----+---------+-------+ |
| | Field                                   | Type          | Null | Key | Default | Extra | |
| +-----------------------------------------+---------------+------+-----+---------+-------+ |
| | noPKhere                                | int(11)       | NO   |     |         |       | |
| +-----------------------------------------+---------------+------+-----+---------+-------+ |
| | veryLongColumnName_And_Then.Some_%_More | decimal(12,2) | YES  |     |         |       | |
| +-----------------------------------------+---------------+------+-----+---------+-------+ |
| | limit                                   | int(11)       | NO   |     |         |       | |
| +-----------------------------------------+---------------+------+-----+---------+-------+ |
|                                                                                            |
| testtable2                                                                                 |
| +-------+---------+------+-----+---------+-------+                                         |
| | Field | Type    | Null | Key | Default | Extra |                                         |
| +-------+---------+------+-----+---------+-------+                                         |
| | id    | int(11) | NO   | PRI |         |       |                                         |
| +-------+---------+------+-----+---------+-------+                                         |
+--------------------------------------------------------------------------------------------+

Note1: A Database called Reporting101a is created to house two stored procedures and some support tables. These routines start by a call a stored procedure referring to the database to be reported on by use of a string.

The data to produce the output is accessed thru the special INFORMATION_SCHEMA database in a READ-only safe manner. As so, the database being reported on is not touched.

There are three non-temporary tables kept in this database.

1. reportDataDefsSession - A simple table used for getting a session#
2. reportDataDefs - data returne from INFORMATION_SCHEMA and massaged a bit. It is session-based.
3. reportOutput - A table for print printing like MySQL's DESCRIBE. It is just a table for putting the output together. It is session-based.

Note2: This INT variable is included as an OUT parameter target, written to, and allows you to wedge your other code in after the First stored procedure prepares the data. It represents a session # that isolates the output for later reporting.

Some environments such as PHP have certain tricks that make this a show-stopper for some programmers. So if you need to combine both stored procedures on your own, then do so (or ask me to separately if you are confused).

In any case, it shows how data or efforts can Chain Together stored procedure calls.

Honestly one of the main reasons I come out with a session # as an OUT parameter is that I know I have to create a CURSOR to get the pretty output. And that requires a Cursor DECLARE at the top of a second stored procedure. And DECLAREs must occur at the top of a stored procedure. So with hands tied, I went this route.

Note3: This is the call to the First stored procedure. It is highly likely that you will be done after this call having TRUE as your 4th parameter. The Stored Procedure is pretty well documented inside of it. The 3rd parameter is for whether or not you want the data deleted from the reporting table for the session #. The delete occurs after any output as a resultset. So, this depends on your choice.

Parameters:

1. the database name to describe all tables like describe myTable
2. the INT OUT parameter to hold the session #
3. boolean: do you want the data deleted from the reporting table at the end
4. boolean: should we auto-call the pretty printing stored procedure that generates describe-like output. If you decide to pass parameter 4 as FALSE, then your output may resemble this:

Note4: Used in cases where you want different output but want the session # to work with. You typically don't need this.

Answer 2

You only need to delete first and last lines of the table output and replace + by | to have a markdown format for table.

as this:

|Field|Type|Null|Key|Default|Extra|
|-----|----|----|---|-------|-----|
|blockheight|int(11)|No|PRI|NULL||
...