Converting a DataTable to an CREATE TABLE + INSERT script for SQL in C#

Question

I need to generate a TSQL script from a DataTable along with the DATA in it. It\'s not a single insert. Beside that, I need the create the table too (same datatable structur

Answer 1

First, I would use this object to build your CREATE TABLE command.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
using System.Data;

namespace Toolkit
{
    public class SqlTableCreator
    {
        #region Instance Variables
        private SqlConnection _connection;
        public SqlConnection Connection
        {
            get { return _connection; }
            set { _connection = value; }
        }

        private SqlTransaction _transaction;
        public SqlTransaction Transaction
        {
            get { return _transaction; }
            set { _transaction = value; }
        }

        private string _tableName;
        public string DestinationTableName
        {
            get { return _tableName; }
            set { _tableName = value; }
        }
        #endregion

        #region Constructor
        public SqlTableCreator() { }
        public SqlTableCreator(SqlConnection connection) : this(connection, null) { }
        public SqlTableCreator(SqlConnection connection, SqlTransaction transaction)
        {
            _connection = connection;
            _transaction = transaction;
        }
        #endregion

        #region Instance Methods
        public object Create(DataTable schema)
        {
            return Create(schema, null);
        }
        public object Create(DataTable schema, int numKeys)
        {
            int[] primaryKeys = new int[numKeys];
            for (int i = 0; i < numKeys; i++)
            {
                primaryKeys[i] = i;
            }
            return Create(schema, primaryKeys);
        }
        public object Create(DataTable schema, int[] primaryKeys)
        {
            string sql = GetCreateSQL(_tableName, schema, primaryKeys);

            SqlCommand cmd;
            if (_transaction != null && _transaction.Connection != null)
                cmd = new SqlCommand(sql, _connection, _transaction);
            else
                cmd = new SqlCommand(sql, _connection);

            return cmd.ExecuteNonQuery();
        }

        public object CreateFromDataTable(DataTable table)
        {
            string sql = GetCreateFromDataTableSQL(_tableName, table);

            SqlCommand cmd;
            if (_transaction != null && _transaction.Connection != null)
                cmd = new SqlCommand(sql, _connection, _transaction);
            else
                cmd = new SqlCommand(sql, _connection);

            return cmd.ExecuteNonQuery();
        }
        #endregion

        #region Static Methods

        public static string GetCreateSQL(string tableName, DataTable schema, int[] primaryKeys)
        {
            string sql = "CREATE TABLE [" + tableName + "] (\n";

            // columns
            foreach (DataRow column in schema.Rows)
            {
                if (!(schema.Columns.Contains("IsHidden") && (bool)column["IsHidden"]))
                {
                    sql += "\t[" + column["ColumnName"].ToString() + "] " + SQLGetType(column);

                    if (schema.Columns.Contains("AllowDBNull") && (bool)column["AllowDBNull"] == false)
                        sql += " NOT NULL";

                    sql += ",\n";
                }
            }
            sql = sql.TrimEnd(new char[] { ',', '\n' }) + "\n";

            // primary keys
            string pk = ", CONSTRAINT PK_" + tableName + " PRIMARY KEY CLUSTERED (";
            bool hasKeys = (primaryKeys != null && primaryKeys.Length > 0);
            if (hasKeys)
            {
                // user defined keys
                foreach (int key in primaryKeys)
                {
                    pk += schema.Rows[key]["ColumnName"].ToString() + ", ";
                }
            }
            else
            {
                // check schema for keys
                string keys = string.Join(", ", GetPrimaryKeys(schema));
                pk += keys;
                hasKeys = keys.Length > 0;
            }
            pk = pk.TrimEnd(new char[] { ',', ' ', '\n' }) + ")\n";
            if (hasKeys) sql += pk;

            sql += ")";

            return sql;
        }

        public static string GetCreateFromDataTableSQL(string tableName, DataTable table)
        {
            string sql = "CREATE TABLE [" + tableName + "] (\n";
            // columns
            foreach (DataColumn column in table.Columns)
            {
                sql += "[" + column.ColumnName + "] " + SQLGetType(column) + ",\n";
            }
            sql = sql.TrimEnd(new char[] { ',', '\n' }) + "\n";
            // primary keys
            if (table.PrimaryKey.Length > 0)
            {
                sql += "CONSTRAINT [PK_" + tableName + "] PRIMARY KEY CLUSTERED (";
                foreach (DataColumn column in table.PrimaryKey)
                {
                    sql += "[" + column.ColumnName + "],";
                }
                sql = sql.TrimEnd(new char[] { ',' }) + "))\n";
            }

            //if not ends with ")"
            if ((table.PrimaryKey.Length == 0) && (!sql.EndsWith(")")))
            {
                sql += ")";
            }

            return sql;
        }

        public static string[] GetPrimaryKeys(DataTable schema)
        {
            List keys = new List();

            foreach (DataRow column in schema.Rows)
            {
                if (schema.Columns.Contains("IsKey") && (bool)column["IsKey"])
                    keys.Add(column["ColumnName"].ToString());
            }

            return keys.ToArray();
        }

        // Return T-SQL data type definition, based on schema definition for a column
        public static string SQLGetType(object type, int columnSize, int numericPrecision, int numericScale)
        {
            switch (type.ToString())
            {
                case "System.String":
                    return "VARCHAR(" + ((columnSize == -1) ? "255" : (columnSize > 8000) ? "MAX" : columnSize.ToString() ) + ")";

                case "System.Decimal":
                    if (numericScale > 0)
                        return "REAL";
                    else if (numericPrecision > 10)
                        return "BIGINT";
                    else
                        return "INT";

                case "System.Double":
                case "System.Single":
                    return "REAL";

                case "System.Int64":
                    return "BIGINT";

                case "System.Int16":
                case "System.Int32":
                    return "INT";

                case "System.DateTime":
                    return "DATETIME";

                case "System.Boolean":
                    return "BIT";

                case "System.Byte":
                    return "TINYINT";

                case "System.Guid":
                    return "UNIQUEIDENTIFIER";

                default:
                    throw new Exception(type.ToString() + " not implemented.");
            }
        }

        // Overload based on row from schema table
        public static string SQLGetType(DataRow schemaRow)
        {
            return SQLGetType(schemaRow["DataType"],
                                int.Parse(schemaRow["ColumnSize"].ToString()),
                                int.Parse(schemaRow["NumericPrecision"].ToString()),
                                int.Parse(schemaRow["NumericScale"].ToString()));
        }
        // Overload based on DataColumn from DataTable type
        public static string SQLGetType(DataColumn column)
        {
            return SQLGetType(column.DataType, column.MaxLength, 10, 2);
        }
        #endregion
    }
}

Then I would use SQL BulkCopy rather than separate INSERT statements.

public static void BulkInsertDataTable(string connectionString, string tableName, DataTable table)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                SqlBulkCopy bulkCopy =
                    new SqlBulkCopy
                    (
                    connection,
                    SqlBulkCopyOptions.TableLock |
                    SqlBulkCopyOptions.FireTriggers |
                    SqlBulkCopyOptions.UseInternalTransaction,
                    null
                    );

                bulkCopy.DestinationTableName = tableName;
                connection.Open();

                bulkCopy.WriteToServer(table);
                connection.Close();
            }
        }