How to execute the statements in .sql file contains Go, single line and multi line comments using C#?

Question

I have a .Sql file containing a number of statements including

Go

--Single-line comments

/* Multi-line comments */

How can I execute this file using c#?

Please suggest to me some ideas.

Thank You:)

Answer 1

Got one solution

Step 1: Add the following class to the solution

public class SqlStatementReader
{
    public class SqlBadSyntaxException : Exception
    {
        public SqlBadSyntaxException(string description) : base(description) { }
        public SqlBadSyntaxException(string description, int line) : base(OnBase(description, line, null)) { }
        public SqlBadSyntaxException(string description, int line, string filePath) : base(OnBase(description, line, filePath)) { }
        private static string OnBase(string description, int line, string filePath)
        {
            if (filePath == null)
                return string.Format("Line: {0}. {1}", line, description);
            else
                return string.Format("File: {0}\r\nLine: {1}. {2}", filePath, line, description);
        }
    }
    enum SqlScriptChunkTypes
    {
        InstructionOrUnquotedIdentifier = 0,
        BracketIdentifier = 1,
        QuotIdentifierOrLiteral = 2,
        DblQuotIdentifierOrLiteral = 3,
        CommentLine = 4,
        CommentMultiline = 5,
    }
    StreamReader _sr = null;
    string _filePath = null;
    int _lineStart = 1;
    int _lineEnd = 1;
    bool _isNextChar = false;
    char _nextChar = '\0';
    public SqlStatementReader(StreamReader sr)
    {
        if (sr == null)
            throw new ArgumentNullException("StreamReader can't be null.");

        if (sr.BaseStream is FileStream)
            _filePath = ((FileStream)sr.BaseStream).Name;

        _sr = sr;
    }
    public SqlStatementReader(StreamReader sr, string filePath)
    {
        if (sr == null)
            throw new ArgumentNullException("StreamReader can't be null.");

        _sr = sr;
        _filePath = filePath;
    }
    public int LineStart { get { return _lineStart; } }
    public int LineEnd { get { return _lineEnd == 1 ? _lineEnd : _lineEnd - 1; } }
    public void LightSyntaxCheck()
    {
        while (ReadStatementInternal(true) != null) ;
    }
    public string ReadStatement()
    {
        for (string s = ReadStatementInternal(false); s != null; s = ReadStatementInternal(false))
        {
            // skip empty
            for (int i = 0; i < s.Length; i++)
            {
                switch (s[i])
                {
                    case ' ': continue;
                    case '\t': continue;
                    case '\r': continue;
                    case '\n': continue;
                    default:
                        return s;
                }
            }
        }
        return null;
    }
    string ReadStatementInternal(bool syntaxCheck)
    {
        if (_isNextChar == false && _sr.EndOfStream)
            return null;

        StringBuilder allLines = new StringBuilder();
        StringBuilder line = new StringBuilder();
        SqlScriptChunkTypes nextChunk = SqlScriptChunkTypes.InstructionOrUnquotedIdentifier;
        SqlScriptChunkTypes currentChunk = SqlScriptChunkTypes.InstructionOrUnquotedIdentifier;
        char ch = '\0';
        int lineCounter = 0;
        int nextLine = 0;
        int currentLine = 0;
        bool nextCharHandled = false;
        bool foundGO;
        int go = 1;

        while (ReadChar(out ch))
        {
            if (nextCharHandled == false)
            {
                currentChunk = nextChunk;
                currentLine = nextLine;

                switch (currentChunk)
                {
                    case SqlScriptChunkTypes.InstructionOrUnquotedIdentifier:

                        if (ch == '[')
                        {
                            currentChunk = nextChunk = SqlScriptChunkTypes.BracketIdentifier;
                            currentLine = nextLine = lineCounter;
                        }
                        else if (ch == '"')
                        {
                            currentChunk = nextChunk = SqlScriptChunkTypes.DblQuotIdentifierOrLiteral;
                            currentLine = nextLine = lineCounter;
                        }
                        else if (ch == '\'')
                        {
                            currentChunk = nextChunk = SqlScriptChunkTypes.QuotIdentifierOrLiteral;
                            currentLine = nextLine = lineCounter;
                        }
                        else if (ch == '-' && (_isNextChar && _nextChar == '-'))
                        {
                            nextCharHandled = true;
                            currentChunk = nextChunk = SqlScriptChunkTypes.CommentLine;
                            currentLine = nextLine = lineCounter;
                        }
                        else if (ch == '/' && (_isNextChar && _nextChar == '*'))
                        {
                            nextCharHandled = true;
                            currentChunk = nextChunk = SqlScriptChunkTypes.CommentMultiline;
                            currentLine = nextLine = lineCounter;
                        }
                        else if (ch == ']')
                        {
                            throw new SqlBadSyntaxException("Incorrect syntax near ']'.", _lineEnd + lineCounter, _filePath);
                        }
                        else if (ch == '*' && (_isNextChar && _nextChar == '/'))
                        {
                            throw new SqlBadSyntaxException("Incorrect syntax near '*'.", _lineEnd + lineCounter, _filePath);
                        }
                        break;

                    case SqlScriptChunkTypes.CommentLine:

                        if (ch == '\r' && (_isNextChar && _nextChar == '\n'))
                        {
                            nextCharHandled = true;
                            currentChunk = nextChunk = SqlScriptChunkTypes.InstructionOrUnquotedIdentifier;
                            currentLine = nextLine = lineCounter;
                        }
                        else if (ch == '\n' || ch == '\r')
                        {
                            currentChunk = nextChunk = SqlScriptChunkTypes.InstructionOrUnquotedIdentifier;
                            currentLine = nextLine = lineCounter;
                        }
                        break;

                    case SqlScriptChunkTypes.CommentMultiline:

                        if (ch == '*' && (_isNextChar && _nextChar == '/'))
                        {
                            nextCharHandled = true;
                            nextChunk = SqlScriptChunkTypes.InstructionOrUnquotedIdentifier;
                            nextLine = lineCounter;
                        }
                        else if (ch == '/' && (_isNextChar && _nextChar == '*'))
                        {
                            throw new SqlBadSyntaxException("Missing end comment mark '*/'.", _lineEnd + currentLine, _filePath);
                        }
                        break;

                    case SqlScriptChunkTypes.BracketIdentifier:

                        if (ch == ']')
                        {
                            nextChunk = SqlScriptChunkTypes.InstructionOrUnquotedIdentifier;
                            nextLine = lineCounter;
                        }
                        break;

                    case SqlScriptChunkTypes.DblQuotIdentifierOrLiteral:

                        if (ch == '"')
                        {
                            if (_isNextChar && _nextChar == '"')
                            {
                                nextCharHandled = true;
                            }
                            else
                            {
                                nextChunk = SqlScriptChunkTypes.InstructionOrUnquotedIdentifier;
                                nextLine = lineCounter;
                            }
                        }
                        break;

                    case SqlScriptChunkTypes.QuotIdentifierOrLiteral:

                        if (ch == '\'')
                        {
                            if (_isNextChar && _nextChar == '\'')
                            {
                                nextCharHandled = true;
                            }
                            else
                            {
                                nextChunk = SqlScriptChunkTypes.InstructionOrUnquotedIdentifier;
                                nextLine = lineCounter;
                            }
                        }
                        break;
                }
            }
            else
                nextCharHandled = false;

            foundGO = false;
            if (currentChunk == SqlScriptChunkTypes.InstructionOrUnquotedIdentifier || go >= 5 || (go == 4 && currentChunk == SqlScriptChunkTypes.CommentLine))
            {
                // go = 0 - break, 1 - begin of the string, 2 - spaces after begin of the string, 3 - G or g, 4 - O or o, 5 - spaces after GO, 6 - line comment after valid GO
                switch (go)
                {
                    case 0:
                        if (ch == '\r' || ch == '\n')
                            go = 1;
                        break;
                    case 1:
                        if (ch == ' ' || ch == '\t')
                            go = 2;
                        else if (ch == 'G' || ch == 'g')
                            go = 3;
                        else if (ch != '\n' && ch != '\r')
                            go = 0;
                        break;
                    case 2:
                        if (ch == 'G' || ch == 'g')
                            go = 3;
                        else if (ch == '\n' || ch == '\r')
                            go = 1;
                        else if (ch != ' ' && ch != '\t')
                            go = 0;
                        break;
                    case 3:
                        if (ch == 'O' || ch == 'o')
                            go = 4;
                        else if (ch == '\n' || ch == '\r')
                            go = 1;
                        else
                            go = 0;
                        break;
                    case 4:
                        if (ch == '\r' && (_isNextChar && _nextChar == '\n'))
                            go = 5;
                        else if (ch == '\n' || ch == '\r')
                            foundGO = true;
                        else if (ch == ' ' || ch == '\t')
                            go = 5;
                        else if (ch == '-' && (_isNextChar && _nextChar == '-'))
                            go = 6;
                        else
                            go = 0;
                        break;
                    case 5:
                        if (ch == '\r' && (_isNextChar && _nextChar == '\n'))
                            go = 5;
                        else if (ch == '\n' || ch == '\r')
                            foundGO = true;
                        else if (ch == '-' && (_isNextChar && _nextChar == '-'))
                            go = 6;
                        else if (ch != ' ' && ch != '\t')
                            throw new SqlBadSyntaxException("Incorrect syntax was encountered while parsing go.", _lineEnd + lineCounter, _filePath);
                        break;
                    case 6:
                        if (ch == '\r' && (_isNextChar && _nextChar == '\n'))
                            go = 6;
                        else if (ch == '\n' || ch == '\r')
                            foundGO = true;
                        break;
                    default:
                        go = 0;
                        break;
                }
            }
            else
                go = 0;

            if (foundGO)
            {
                if (ch == '\r' || ch == '\n')
                {
                    ++lineCounter;
                }
                // clear GO
                string s = line.Append(ch).ToString();
                for (int i = 0; i < s.Length; i++)
                {
                    switch (s[i])
                    {
                        case ' ': continue;
                        case '\t': continue;
                        case '\r': continue;
                        case '\n': continue;
                        default:
                            _lineStart = _lineEnd;
                            _lineEnd += lineCounter;
                            return allLines.Append(s.Substring(0, i)).ToString();
                    }
                }
                return string.Empty;
            }

            // accumulate by string
            if (ch == '\r' && (_isNextChar == false || _nextChar != '\n'))
            {
                ++lineCounter;
                if (syntaxCheck == false)
                    allLines.Append(line.Append('\r').ToString());
                line.Clear();
            }
            else if (ch == '\n')
            {
                ++lineCounter;
                if (syntaxCheck == false)
                    allLines.Append(line.Append('\n').ToString());
                line.Clear();
            }
            else
            {
                if (syntaxCheck == false)
                    line.Append(ch);
            }
        }

        // this is the end of the stream, return it without GO, if GO exists
        switch (currentChunk)
        {
            case SqlScriptChunkTypes.InstructionOrUnquotedIdentifier:
            case SqlScriptChunkTypes.CommentLine:
                break;
            case SqlScriptChunkTypes.CommentMultiline:
                if (nextChunk != SqlScriptChunkTypes.InstructionOrUnquotedIdentifier)
                    throw new SqlBadSyntaxException("Missing end comment mark '*/'.", _lineEnd + currentLine, _filePath);
                break;
            case SqlScriptChunkTypes.BracketIdentifier:
                if (nextChunk != SqlScriptChunkTypes.InstructionOrUnquotedIdentifier)
                    throw new SqlBadSyntaxException("Unclosed quotation mark [.", _lineEnd + currentLine, _filePath);
                break;
            case SqlScriptChunkTypes.DblQuotIdentifierOrLiteral:
                if (nextChunk != SqlScriptChunkTypes.InstructionOrUnquotedIdentifier)
                    throw new SqlBadSyntaxException("Unclosed quotation mark \".", _lineEnd + currentLine, _filePath);
                break;
            case SqlScriptChunkTypes.QuotIdentifierOrLiteral:
                if (nextChunk != SqlScriptChunkTypes.InstructionOrUnquotedIdentifier)
                    throw new SqlBadSyntaxException("Unclosed quotation mark '.", _lineEnd + currentLine, _filePath);
                break;
        }

        if (go >= 4)
        {
            string s = line.ToString();
            for (int i = 0; i < s.Length; i++)
            {
                switch (s[i])
                {
                    case ' ': continue;
                    case '\t': continue;
                    case '\r': continue;
                    case '\n': continue;
                    default:
                        _lineStart = _lineEnd;
                        _lineEnd += lineCounter + 1;
                        return allLines.Append(s.Substring(0, i)).ToString();
                }
            }
        }

        _lineStart = _lineEnd;
        _lineEnd += lineCounter + 1;
        return allLines.Append(line.ToString()).ToString();
    }
    bool ReadChar(out char ch)
    {
        if (_isNextChar)
        {
            ch = _nextChar;
            if (_sr.EndOfStream)
                _isNextChar = false;
            else
                _nextChar = Convert.ToChar(_sr.Read());
            return true;
        }
        else if (_sr.EndOfStream == false)
        {
            ch = Convert.ToChar(_sr.Read());
            if (_sr.EndOfStream == false)
            {
                _isNextChar = true;
                _nextChar = Convert.ToChar(_sr.Read());
            }
            return true;
        }
        else
        {
            ch = '\0';
            return false;
        }
    }
    public static int ExecuteSqlFile(string filePath, SqlConnection connection, Encoding fileEncoding, int commandTimeout)
    {
        int rowsAffected = 0;
        using (FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read))
        {
            // Simple syntax check (you can comment out these two lines below)
            new SqlStatementReader(new StreamReader(fs, fileEncoding)).LightSyntaxCheck();
            fs.Seek(0L, SeekOrigin.Begin);

            // Read statements without GO
            SqlStatementReader rd = new SqlStatementReader(new StreamReader(fs, fileEncoding));
            string stmt;
            while ((stmt = rd.ReadStatement()) != null)
            {
                using (SqlCommand cmd = connection.CreateCommand())
                {
                    cmd.CommandText = stmt;
                    cmd.CommandTimeout = commandTimeout;
                    int i = cmd.ExecuteNonQuery();
                    //if (i > 0)
                    rowsAffected += i;
                }
            }
        }
        return rowsAffected;

    }
}

Step 2: Call the following function with valid parameters

SqlStatementReader.ExecuteSqlFile(fileLocation + "\\FileName.sql", conObject, Encoding.Default, 0);

Answer 2

The comments should just work as-is, but GO is not part of the the SQL language! It's just a convenience provided by tools like SSMS to separate batches, and we will have to account for it manually.

To do that, we can use code like this:

public void ExecuteFile(string filePath)
{
    using var con = new SqlConnection("connection string here");
    var var cmd = new SqlCommand("", con);
    con.Open();

    var builder = new StringBuilder();
    var lines = File.ReadLines(filePath);
    foreach(var line in lines)
    {     
        // GO is only a batch separator if it's on the line with just itself and whitespace
        // Not even semicolon is allowed.
        // Not usually a fan of ToUpper() (or Lower()) for case insensitive compares, but it IS enough in this case.
        // This regex would also work: ^\s*[Gg][Oo]\s*$
        var sep = line.Trim();
        if (sep.Length == 2 && sep.ToUpper() == "GO")
        { 
            // This is a batch separator!

            if (builder.Length > 0)
            {
                cmd.CommandText = builder.ToString();
                cmd.ExecuteNonQuery(); //NonQuery because we don't care about the results. We're just running statements in the file.
                builder = new StringBuilder();
            }
        }
        else
        {
            builder.AppendLine(line);
        }
    }
    if (builder.Length > 0)
    {
        cmd.CommandText = builder.ToString();
        cmd.ExecuteNonQuery();
    }
}

There is one bug here: this isn't smart enough to recognize a batch separator inside a multiline block comment (/* */). And if I made it smart enough to recognize block comments, then it wouldn't be smart enough to spot whether those tokens are inside string literals.

The point I'm making is, to really do this right, you eventually end up in a place where you've written a complete and valid SQL parser, which is... well it's not trivial.