How to copy a database table structure (T-SQL Scripting Series)

Problem

Do you recognize the need to copy a table structure in MS SQL Server, for temporary or permanent usage?

Most of you will know the famous

Insert Into Example.sql
SELECT TOP 0 *
INTO [dbo].[some unexisting table]
FROM [dbo].[some existing table]

But this approach has some limitations: Computed columns change into regular columns, and primary and foreign keys are not copied. Sometimes you just need more than this.

Solution

So I have made a script to copy a SQL server table structure with foreign keys but without indexes.
This script handles user defined types and computed columns gracefully.

My credits go to Aaron Bertand (see his post on mssqltips). I used his script for copying the foreign keys and added my own parts to it (download it here).

TSQL-S01E01-copy_table

TSQL-S01E01-CopyTableStructure.sql

--\
---) Author: Hans Michiels
---) Script to copy a sql server table structure with foreign keys but without indexes.
---) This script handles user defined types and computed columns gracefully.
--/
/*
(c) Copyright 2016 - hansmichiels.com
 
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/

--\
---) VARIABLES DECLARATIONS
--/
DECLARE @CrLf NVARCHAR(2)
DECLARE @Indent NVARCHAR(2)
DECLARE @nsql NVARCHAR(MAX)
DECLARE @SimulationMode CHAR(1)
DECLARE @SourceSchemaAndTable NVARCHAR(260)
DECLARE @TargetSchemaAndTable NVARCHAR(260)
DECLARE @FkNameSuffix NVARCHAR(128)
DECLARE @TableOptions NVARCHAR(500)

--\
---) CONFIGURATION: set the source and target schema/tablename here, and some other settings.
--/
SELECT
    @SimulationMode = 'Y' -- Use Y if you only want the SQL statement in the output window without it being executed.
  , @SourceSchemaAndTable = '[dbo].[Order]'
  , @TargetSchemaAndTable = '[dbo].[OrderCopy]'
  , @TableOptions = ' WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY]'
  , @FkNameSuffix = '_' + REPLACE(CAST(NEWID() AS VARCHAR(40)), '-', '') -- A Guid is added to the foreign key name to make it unique.
  , @CrLf = CHAR(13) + CHAR(10)
  , @Indent = SPACE(2)
  -- For 'min' script use this (in case sql is near 4000 characters):
  -- , @CrLf = ' '
  -- , @Indent = ''

--\
---) BUILD SQL FOR CLONING TABLE
--/
SELECT @nsql
    = ISNULL(@nsql, '')
    + CASE col_sequence WHEN 1 THEN
      @CrLf + 'IF OBJECT_ID(N''' + @TargetSchemaAndTable + ''', ''U'') IS NOT NULL DROP TABLE ' + @TargetSchemaAndTable + ';'
    + @CrLf + 'CREATE TABLE ' + @TargetSchemaAndTable + @CrLf + @Indent + '( ' ELSE @CrLf + @Indent + ', ' END
    + [definition]
FROM (
      SELECT ROW_NUMBER() OVER (PARTITION BY tb.object_id ORDER BY tb.object_id, col.column_id) AS col_sequence
        , QUOTENAME(col.name) + ' '
        + COALESCE(
            'AS ' + cmp.definition + CASE ISNULL(cmp.is_persisted, 0) WHEN 1 THEN ' PERSISTED ' ELSE '' END,
            CASE
              WHEN col.system_type_id != col.user_type_id THEN QUOTENAME(usr_tp.schema_name) + '.' + QUOTENAME(usr_tp.name)
              ELSE
                QUOTENAME(sys_tp.name) +
                CASE
                  WHEN sys_tp.name IN ('char', 'varchar', 'binary', 'varbinary') THEN '(' + CONVERT(VARCHAR, CASE col.max_length WHEN -1 THEN 'max' ELSE CAST(col.max_length AS varchar(10)) END) + ')'
                  WHEN sys_tp.name IN ('nchar', 'nvarchar') THEN '(' + CONVERT(VARCHAR, CASE col.max_length WHEN -1 THEN 'max' ELSE CAST(col.max_length/2 AS varchar(10)) END) + ')'
                  WHEN sys_tp.name IN ('decimal', 'numeric') THEN '(' + CAST(col.precision AS VARCHAR) + ',' + CAST(col.scale AS VARCHAR) + ')'
                  WHEN sys_tp.name IN ('datetime2') THEN '(' + CAST(col.scale AS VARCHAR) + ')'
                  ELSE ''
                END
            END
            )
        + CASE col.is_nullable
            WHEN 0 THEN ' NOT NULL'
            ELSE CASE WHEN cmp.definition IS NULL THEN ' NULL' ELSE ' ' END
          END AS [definition]
       FROM sys.tables tb
       JOIN sys.schemas sch
         ON sch.schema_id = tb.schema_id
       JOIN sys.columns col
         ON col.object_id = tb.object_id
       JOIN sys.types sys_tp
         ON col.system_type_id = sys_tp.system_type_id
        AND col.system_type_id = sys_tp.user_type_id
       LEFT JOIN
            (
            SELECT tp.*, sch.name AS [schema_name]
            FROM sys.types tp
            JOIN sys.schemas sch
            ON tp.schema_id = sch.schema_id
            ) usr_tp
         ON col.system_type_id = usr_tp.system_type_id
        AND col.user_type_id = usr_tp.user_type_id
       LEFT JOIN sys.computed_columns cmp
         ON cmp.object_id = tb.object_id
        AND cmp.column_id = col.column_id
      WHERE tb.object_id = OBJECT_ID(@SourceSchemaAndTable, 'U')
      ) subqry
;
SELECT @nsql
    = ISNULL(@nsql, '')
    + CASE col_sequence
        WHEN 1 THEN @CrLf + ', PRIMARY KEY ' + CASE is_clustered_index WHEN 1 THEN 'CLUSTERED' ELSE 'NONCLUSTERED' END
           + @CrLf + @Indent + '( '
        ELSE @CrLf + @Indent + ', '
      END
    + QUOTENAME(pk_cols.column_name)
    + CASE is_descending_key
        WHEN 1 THEN ' DESC'
        ELSE ' ASC'
      END
FROM (
      SELECT TOP 2147483647 sch.name as schema_name, tb.name as table_name, col.name as column_name
               , ROW_NUMBER() OVER (PARTITION BY tb.object_id ORDER BY tb.object_id, ic.key_ordinal) AS col_sequence
               , ic.is_descending_key
               , CASE WHEN idx.index_id = 1 THEN 1 ELSE 0 END AS [is_clustered_index]
       FROM sys.tables tb
       JOIN sys.schemas sch
         ON sch.schema_id = tb.schema_id
       JOIN sys.indexes idx
         ON idx.is_primary_key = 1
        AND idx.object_id = tb.object_id
       JOIN sys.index_columns ic
         ON is_included_column = 0
        AND ic.object_id = tb.object_id
        AND ic.index_id = idx.index_id
       JOIN sys.columns col
         ON col.column_id = ic.column_id
        AND col.object_id = tb.object_id
      WHERE tb.object_id = OBJECT_ID(@SourceSchemaAndTable, 'U')
      ORDER BY tb.object_id, ic.key_ordinal
      ) pk_cols
 
SELECT @nsql = @nsql + @CrLf + @indent + ') ' + @TableOptions

IF @SimulationMode = 'Y'
BEGIN
  PRINT '-- Simulation mode: script is not executed.'
END
PRINT @nsql;
IF @SimulationMode != 'Y'
BEGIN
  EXEC(@nsql);
END
 
--\
---) Copy foreign key constraints
---) A guid is added to the foreign key name to make it unique within the database.
--/
SET @nsql = N'';
SELECT @nsql += N'
ALTER TABLE '

      + @TargetSchemaAndTable
      + ' ADD CONSTRAINT [' + LEFT(fk.name + @FkNameSuffix, 128) + '] '
      + ' FOREIGN KEY (' + STUFF((SELECT ',' + QUOTENAME(col.name)
      -- get all the columns in the constraint table
      FROM sys.columns AS col
      JOIN sys.foreign_key_columns AS fkc
        ON fkc.parent_column_id = col.column_id
        AND fkc.parent_object_id = col.[object_id]
      WHERE fkc.constraint_object_id = fk.[object_id]
      ORDER BY fkc.constraint_column_id
      FOR XML PATH(N''), TYPE).value(N'.[1]', N'nvarchar(max)'), 1, 1, N'')
      + ') REFERENCES ' + QUOTENAME(rs.name) + '.' + QUOTENAME(rtb.name)
      + '('
      + STUFF((SELECT ',' + QUOTENAME(col.name)
      -- get all the referenced columns
      FROM sys.columns AS col
      JOIN sys.foreign_key_columns AS fkc
        ON fkc.referenced_column_id = col.column_id
       AND fkc.referenced_object_id = col.[object_id]
      WHERE fkc.constraint_object_id = fk.object_id
      ORDER BY fkc.constraint_column_id
      FOR XML PATH(N''), TYPE).value(N'.[1]', N'nvarchar(max)'), 1, 1, N'') + ');'
FROM sys.foreign_keys AS fk
JOIN sys.tables AS rtb -- referenced table
   ON fk.referenced_object_id = rtb.[object_id]
JOIN sys.schemas AS rs
   ON rtb.[schema_id] = rs.[schema_id]
JOIN sys.tables AS ctb -- constraint table
   ON fk.parent_object_id = ctb.[object_id]
WHERE rtb.is_ms_shipped = 0 AND ctb.is_ms_shipped = 0
  AND ctb.object_id = OBJECT_ID(@SourceSchemaAndTable, 'U');

IF @SimulationMode = 'Y'
BEGIN
  PRINT '-- Simulation mode: script is not executed.'
END
PRINT @nsql;
IF @SimulationMode != 'Y'
BEGIN
  EXEC(@nsql);
END

Download the script here.

Conclusion / Wrap up

With this script you can copy the structure of a table including primary and foreign keys, computed columns and columns using a user defined datatype.
Last updated: 14 July, 2016.

(c) 2016 hansmichiels.com – Do not steal the contents – spread the link instead – thank you.

Hans Michiels

Hans Michiels

Hans is an Independent Business Intelligence and Datawarehouse Consultant & Microsoft SQL Server Consultant, working in the Netherlands. He has been working in the software industry since 1996, with SQL Server since the year 2001, and since 2008 he has a primary focus on datawarehouse- and business intelligence projects using Microsoft technology, using a Datavault and Kimball architecture. He has a special interest in Datawarehouse Automation and Metadata driven solutions. * Certified in Data Vault Modeling: Certified Data Vault 2.0 Practitioner, CDVDM (aka Data Vault 1.0) * Certified in MS SQL Server: * MCSA (Microsoft Certified Solutions Associate) SQL Server 2012 - MCITP Business Intelligence Developer 2005/2008 - MCITP Database Developer 2005/2008 - MCITP Database Administrator 2005/2008

More Posts

9 thoughts on “How to copy a database table structure (T-SQL Scripting Series)”

  1. Excellent !!! Just do one change .. make @nsql NVARCHAR(MAX) to Varchar(max) . for large table which have more than 100 columns & 40 – 50 FKs It is not working. varchar took 1 byte per character so capacity is increased up to 2 billion characters.

    1. Hi Shwetamber, good to hear that my script is of use to you and thank you for the suggestion to change the NVARCHAR(MAX) column to VARCHAR(MAX).

  2. Hi. I had a quick look. And I think, that, actually, your script does not work well.

    I can explain a few mistakes:

    1) Primary key section:
    `
    SELECT TOP 2147483647 sch.name as schema_name, tb.name as table_name, col.name as column_name
    , ROW_NUMBER() OVER (PARTITION BY tb.object_id ORDER BY tb.object_id, col.column_id) AS col_sequence
    `
    If you have composite indexes to get true ‘ORDER BY’ you should use the column *ic.key_ordinal*, otherwise you cannot guarantee true sort.

    2) Computed columns and NULL values. If you try to use your script with computed columns you will get an error.
    I think you guess about the issue, when you take a look to this:
    `
    + CASE
    WHEN col.is_nullable = 0 THEN ‘ NOT NULL’
    WHEN cmp.is_nullable = 1 and cmp.is_persisted = 0 THEN ”
    WHEN cmp.is_nullable = 0 and cmp.is_persisted = 1 THEN ‘ NOT NULL’
    ELSE ‘ NULL’
    END AS [definition]
    `
    3) Convert columns to string with `CASE…` is undocumented feature. I suggest to use XML.

    1. Hello Denis,

      You have three points, I will discuss them one by one.

      1) However in my use cases it always worked well, but that does not mean you cannot be right and that in rare cases ic.key_ordinal would give a better sorting.
      2) I have used this script with computed columns and it worked perfectly. It seems that you only looked at the script and think that it does not work. If this is not the case, please provide me with a sql script that creates a table that cannot be copied using my script.
      3) I do not understand this. The script builds and executes dynamic SQL, not XML. I am not sure where you want me to use XML.

      Best regards,
      Hans

      1. Thank you for you answer Hans,

        Lets check your script with a test table:

        CREATE TABLE [dbo].[Order](
        [OrderID] [int] NOT NULL,
        [OrderName] [varchar](20) NOT NULL,
        [Col3] [int] NOT NULL,
        [Col4] [int] NOT NULL,
        [Col5] [varchar](256) NOT NULL,
        [Col6] [varchar](max) NOT NULL,
        [Col7] [int] NOT NULL,
        [StartDate] [date] NULL,
        [EndDate] [datetime] NOT NULL,
        [Calc_column] AS ((2)*[Col4]),
        CONSTRAINT [PK_DataRequestChild] PRIMARY KEY CLUSTERED
        (
        [OrderID] ASC,
        [Col7] ASC,
        [Col4] ASC
        )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON)
        )
        ———————-
        Your script creates the following table:

        IF OBJECT_ID(N'[dbo].[OrderCopy]’, ‘U’) IS NOT NULL DROP TABLE [dbo].[OrderCopy];
        CREATE TABLE [dbo].[OrderCopy]
        ( [OrderID] [int] NOT NULL
        , [OrderName] [varchar](20) NOT NULL
        , [Col3] [int] NOT NULL
        , [Col4] [int] NOT NULL
        , [Col5] [varchar](256) NOT NULL
        , [Col6] [varchar](max) NOT NULL
        , [Col7] [int] NOT NULL
        , [StartDate] [date] NULL
        , [EndDate] [datetime] NOT NULL
        , [Calc_column] AS ((2)*[Col4]) NULL
        , PRIMARY KEY CLUSTERED
        ( [OrderID] ASC
        , [Col4] ASC
        , [Col7] ASC
        ) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY]

        1) Sorting is wrong
        2) Cannot create the table:
        Only UNIQUE or PRIMARY KEY constraints can be created on computed columns, while CHECK, FOREIGN KEY, and NOT NULL constraints require that computed columns be persisted.

        1. Hello Denis, thank you for your example table.
          I always used the script for tables with a single-column primary key and computed columns on non-primary key columns, this explains why those tables could be copied using the script. But using your table example, I have now updated the script to handle those ‘exceptional’ table designs. Thanks for providing it.
          “DISCLAIMER”: My script is still provided “AS IS” in the hope that it will be useful ..

  3. Hi Hans,
    I have an issue of copy structure table in Azure database how can I copy the structure of a table into another DB in Azure? I need a query for it. I appreciate if you help me.
    Thanks
    Masoud

    1. Hi Masoud,
      Thanks for your question. Sorry to say that I do not have that script and currently do not have the time to build it.
      Best regards,
      Hans

Leave a Reply to Denis Agiev Cancel reply

Your e-mail address will not be published. Required fields are marked *