Table Loads

Introduction

You can import data from text files into an interim table in Priority from tab-delimited text files (Excel files can be converted into tab-delimited files using a utility program). During the execution of this table load, you can perform additional processing defined in a set of SQL statements (a load query). Results of the load can be viewed - and revised - in a form based on the interim table. Finally, a procedure can be used to transfer the final data to a regular Priority form (e.g., ORDERS), using the form load defined above.

In general, a table load interface is characterized by:

  • a unique load file name
  • a specified table or a load query which defines how the load is performed
  • input fields defined as variables, which can be included in the load query
  • parameters affecting the load.

These definitions are recorded in the Characteristics for Download form and its sub-levels (System Management → Database Interface → Table Load (Interfaces)).

Defining the Load File

Any load files, which must use ASCII or Unicode encoding, should be stored in the system\load directory or one of its sub-directories (specifically, the sub-directory for a particular Priority company). Its file name must match the name of the load file defined in the Characteristics for Download form.

Note: Priority's interface tools can import data from either ASCII or Unicode (UTF-16) files, and will automatically recognize the format used. Data exported from Priority for use in outgoing interfaces will be saved in ASCII format, unless otherwise specified.

This name is subject to the following restrictions:

  • It may consist of up to 20 characters
  • Only alphanumeric values (uppercase and lowercase letters and digits) and the underline sign may be used (no spaces).
  • The name must begin with a letter.
  • You may not use a reserved word.
  • The name assigned to any newly created form load should include a common four-letter prefix (the same one you use for all entities that you add to Priority for the customer in question; e.g., XXXX_LOADFNC2).

If the file in question is stored in a company sub-directory, also flag the Sub-directory column (and make sure you run the load from the correct company). If data is separated by tabs, flag the Tab Separator column. You may also specify a brief description of the load file in the Description of Data column.

Defining the Load

You have two options in defining the load:

  • You can designate the load table and have Priority create an automatic query, or
  • You can record the load query manually.

In both cases you must also define the input file. This consists of all table columns (in the case of an automatic query), or the variables that are input in each field (in the case of a manual query).

The automatic query inserts all data in the input file into the columns of the specified table. Of course, the input file must contain all unique key columns in the target table (with identical names) in order for the load to succeed. It need not contain the autounique key; if there is no value for this key, it will be assigned automatically during the insert.

A manual query should be constructed if you want to add processing during the table load. This is a set of SQL statements which determine how the load is to be executed. The statements that make up the load query are executed upon each line of the input file, one at a time.

Automatic Load Query

To make use of the automatic load query, designate the name of the table in the Table for Auto Load column of the Characteristics of Download form. Then define the input file in the sub-level form, Input Record Fields. In the Variable column, record the name of each table column into which data should be inserted. Indicate its type and position (first and last character). You can also add a description in the Title column.

Note: In a file with tab separators, column width is meaningless.

Manual Load Query

If you want to record a query manually, first define the input file in the Input Record Fields sub-level form. On each line, record a variable that is input into a field, to be used in the load query. For each variable, designate its type and define its position within the file. You can also add a description (in the Title column).

Note: In a file with tab separators, variable width is meaningless.

Next, record the SQL statements making up the query in the Load Query sub-level form. You can include ERRMSG and WRNMSG commands. An error message (ERRMSG) will cause the load of a given input line to fail. The error message is then written in the ERRMSGS table. The failure to load one input line has no effect on the loading of another. A warning message is also written to the ERRMSGS table, but does not cause the input line to fail. Like in forms and procedures, you can use message parameters :PAR1, :PAR2 and :PAR3. The messages themselves should be recorded in the Error & Warning Messages form. SQL statements are stored in the LOADTEXT table; messages are stored in the LOADMSG table.

Tips:

  • To check the SQL statements in your load query for syntax errors, prior to activation of the load, run the Check Syntax program by Action from within the Characteristics for Download form.
  • You can track changes to load queries once they have been included in prepared version revisions. See Tracking Changes to Queries.

Loading the File

There are several ways to execute a table load:

  • Run the Download a File program from the Table Load (Interfaces) menu.
  • Activate the load from an SQLI step of a procedure, using the following syntax (parameters are explained in the next section):
EXECUTE DBLOAD -L, loadname, ['-i', 'input_file'], ['-I'],
 ['-T', 'table', 'linkfile'], ['-g', 'debug_file'], ['-ns'],
  ['-N'], ['-E', 'unloaded_file'], ['-M'], ['-C'], ['-B'], 
['-U'], ['-u'], ['-v'], ['msgfile'];
  • Include the table load as a load step (type L) in a procedure, indicating the file name as the first parameter. You can use the same parameters as in the previous option, except that they are listed in the Procedure Parameters form (sub-level form of Procedure Steps).

Note: The last two methods offer more options than the first.

Table Load Parameters

  • 'loadname' — The File Name used to identify the table load in the Characteristics for Download form (also the name of the load file).
  • ‘-I’ (uppercase "i") — Use this option when you want the DBLOAD program to input data from the file.in file (stored in the system\load directory). Alternatively, use the ['-i', 'input_file'] option to specify a different input file.
  • ‘-T’, table, linkfile — Use this option when you want the DBLOAD program to load data to a linked copy of the designated table.
  • '-g', 'debug_file' — This option creates a file that displays each query and its execution. This is similar to other Priority debugging tools that offer the –g option (see Debug Tools).
  • ‘-ns’ — By default, the INTERFACE program displays a progress bar as the load is executed. Use this option to disable this utility.
  • '-N' — Use this option if you do not want the INTERFACE program to clear the ERRMSGS table when executing a load. Instead, the program will append the contents of the newest unloaded file and message file to the ERRMSGS table (see below).
  • '-E', 'unloaded_file' — Use these parameters to create a file of all lines from the input file that failed to be loaded. This file will be stored in the system\load directory, unless another path is specified. It can then serve as an input file in its own right, once the problem that caused the load to fail has been solved.
  • ‘-M’ — Use this option to have the INTERFACE program rename the input file to file.bak .
  • ‘-C’ — If the load table contains numeric values formatted as strings, use this option to have the INTERFACE program remove commas from any numbers that appear in strings.
  • ‘-B’ — Use this option to have the INTERFACE program remove any text enclosed in square brackets.
  • ‘-U’ — If the load table contains a USERS column, use this option to have the INTERFACE program ignore data in this column (data are inserted with USER = 0).
  • ‘-u’ — Use this option if you want the INTERFACE program to specify the current user when messages are inserted into the ERRMSGS table. Otherwise, messages are inserted with USER = 0.
  • '-v' – Use this option if you want the DBLOAD program to check the structure of the input file. If the type of a value (e.g., INT, REAL, DATE) is incompatible with the expected type for that position, an error is generated and the file will not be loaded.
  • 'msgfile' — The name of the file in which to hold messages. This file will be stored in the directory from which the DBLOAD was activated (system\load or system\load\company), unless another path is specified. It contains the following:
    • A message indicating how many lines of the input file have been successfully loaded.
    • In the case of a fatal error (the structure of the input file was not defined, there was no load query or there was a syntax error in one of the SQL statements), a message explaining why the load failed altogether.

Viewing Load Messages

Any messages (error/warning) generated by the DBLOAD program will appear in the Download Messages report (DBLOADERRS). These messages are stored in the ERRMSGS table with the value L in the TYPE column, and USER = 0 (or USER = SQL.USER if you use the ‘-u’ option. In every execution of a load, the messages from the previous execution are deleted (unless you use the -N option).

Converting an Excel File to a Tab-delimited Text File for DBLOAD

Use the EXL2TXT command (from a trigger or Step Query of an SQLI step) to convert an .xlsx file to the tab-delimited text file required for table loads.

Example:

EXECUTE WINAPP 'p:\bin.95', '-w', 'EXL2TXT.exe', :F, :T; 
/* where p:> represents the full path to bin.95) */

The file is created with UTF-16 encoding.

Further Reading