在 C# 中将 DataTable 转换为 SQL 的 CREATE TABLE + INSERT 脚本答案

【问题标题】：Converting a DataTable to an CREATE TABLE + INSERT script for SQL in C#在 C# 中将 DataTable 转换为 SQL 的 CREATE TABLE + INSERT 脚本
【发布时间】：2011-07-10 18:47:48
【问题描述】：

我需要从 DataTable 以及其中的 DATA 生成 TSQL 脚本。这不是一个单一的插入。除此之外，我也需要创建表（相同的数据表结构）

所以：我有一个填充数据的 DataTable。我想要创建此 DataTable 结构的 TSQL 脚本以及 SQL SERVER 中的数据（CREATE TABLE + INSERT）

提前谢谢你并且特别感谢 John Saunders 帮助我更正了这个问题。

【问题讨论】：

您使用的是哪个版本的 .NET？ DataTable 是相当原始的技术，没有内置的方式来做你想要的。
我使用的是 Framework 3.5 vs 2010
那么您应该查看实体框架，它具有创建数据库模型、创建表然后更新它的能力。 DataTable 已经过时了。
在我的情况下提供了一个数据表，我需要创建一个数据集来获取结构吗？要读取数据表中的每一行，我可以这样做并附加它并插入一串字符串。 For Each iRow as Datarow in dtTable string strSQL = "INSERT INTO TestTable(Col1,Col2) VALUES (" + iRow.item("Col1") + "," + iRow.item("Col1") + ")";
废话，DataTable 并没有“过时”。实体框架对于很多项目来说都是多余的。

标签： c# sql tsql datatable

【解决方案1】：

看看：Generate SQL INSERT commands programmatically

本质上，代码是循环遍历 DataTable.Columns 集合以生成 INSERT 语句的列列表。然后它循环遍历 DataTable 的值以创建具有值的参数。

【讨论】：

【解决方案2】：

首先，我会用这个对象来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<string> keys = new List<string>();

            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
    }
}

然后我会使用 SQL BulkCopy 而不是单独的 INSERT 语句。

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();
            }
        }

【讨论】：

您的 VARCHAR 缺少结束括号。试试这个 VARCHAR(" + ((table.Columns[i].MaxLength == -1) ? "255), " : (table.Columns[i].MaxLength > 8000) ? "MAX), " : table.Columns [i].MaxLength.ToString() + "), "));

【解决方案3】：

如果您想从表中创建insert 脚本，请使用我创建的工具。这会根据给定的条件在多个表上创建 Insert 脚本：

IF NOT EXISTS (Select 1 from Table1 WHERE Col1='Col1' AND Col2='Col2')
INSERT INTO Table1 (Col1,Col2,Col3,Col4) VALUES (1,'abc',null,'2012-01-01')

这里是链接：http://www.codeproject.com/Tips/330864/Generate-Insert-script-to-extract-data

【讨论】：

那篇文章我看了两遍，但不清楚它在做什么。

【解决方案4】：

public void createsqltable(DataTable dt,string tablename)
        {
            string strconnection = "";
            string table = "";
            table += "IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[" + tablename + "]') AND type in (N'U'))";
            table += "BEGIN ";
            table += "create table " + tablename + "";
            table += "(";
            for (int i = 0; i < dt.Columns.Count; i++)
            {
                if (i != dt.Columns.Count-1)
                    table += dt.Columns[i].ColumnName + " " + "varchar(max)" + ",";
                else
                    table += dt.Columns[i].ColumnName + " " + "varchar(max)";
            }
            table += ") ";
            table += "END";
            InsertQuery(table,strconnection);
            CopyData(strconnection, dt, tablename);
        }
        public void InsertQuery(string qry,string connection)
        {


            SqlConnection _connection = new SqlConnection(connection);
            SqlCommand cmd = new SqlCommand();
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = qry;
            cmd.Connection = _connection;
            _connection.Open();
            cmd.ExecuteNonQuery();
            _connection.Close();
        }
        public static void CopyData(string connStr, DataTable dt, string tablename)
        {
            using (SqlBulkCopy bulkCopy =
            new SqlBulkCopy(connStr, SqlBulkCopyOptions.TableLock))
            {
                bulkCopy.DestinationTableName = tablename;
                bulkCopy.WriteToServer(dt);
            }
        }

【讨论】：

我在dt.Columns[i].ColumnName 上添加了花括号，以防止列名包含空格时引发错误