Thursday, October 2, 2014

Defining SQL tables using a reference file, continued

sql create table like

Yesterday I showed how to create SQL tables using a reference file. Tommaso Arcieri message me with another approach, defining a table based on another file or table.

In this example I am going to use the physical file TESTFILE as the original reference file.

  A          R TESTFILER
  A            FLD001        10
  A            FLD002         3P 0
  A            FLD003        10
  A            FLD004         5P 0
  A            FLD005         9P 2
  A            FLD006         7P 2
  A            FLD007         1
  A            FLD008         1
  A          K FLD001

This just a small file of only eight fields, so it would not be a big deal to enter each field name. But for a field with many more fields it would be a pain to do so. Fortunately the approach Tommaso showed me should be used if the original reference file has only one field or hundreds.

I will be using the CREATE TABLE as I did yesterday, but I will not be using a SELECT to list the columns I want in the table. As I want all the fields in TESTFILE to be columns in my new table I use a LIKE clause:

  CREATE TABLE MYLIB/TESTFILE2
     LIKE TESTFILE
     RCDFMT FORMAT2

As expected the LIKE clause specifies that the columns in the new table will be exactly the same as the fields or columns in the original reference file. If I run the 'Display File Field Description' command, DSPFFD, you can see that the columns are the same as the original file:

             Data        Field
  Field      Type       Length
  FLD001     CHAR           10
  FLD002     PACKED       3  0
  FLD003     CHAR           10
  FLD004     PACKED       5  0
  FLD005     PACKED       9  2
  FLD006     PACKED       7  2
  FLD007     CHAR            1
  FLD008     CHAR            1

If your new table is not in the library QTEMP you can add a key to it using ALTER TABLE:

  ALTER TABLE MYLIB TESTFILE2
     ADD PRIMARY KEY (FLD003,FLD004)

If the new table is in QTEMP you need to read Add key to SQL table in QTEMP.

You can see how to add the equivalent of Column Headings and Text using LABEL ON COLUMN in yesterday's post.

 

More information about CREATE TABLE can be found on the IBM website here.

 

This article was written for IBM i 7.1, and it should work with earlier releases too.

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