Getting LOAD DATA to Cough Up More Information

10.9.1 Problem

LOAD DATA doesn't tell you much about problems in the datafile.

10.9.2 Solution

There is no solution. Well, maybe there is.

10.9.3 Discussion

When a LOAD DATA statement finishes, it returns a line of information that tells you how many errors or data conversion problems occurred. Suppose you load a file into a table and see the following message when LOAD DATA finishes.

Records: 134 Deleted: 0 Skipped: 2 Warnings: 13

These values provide some general information about the import operation:

  • Records indicates the number of records found in the file.
  • Deleted and Skipped are related to treatment of input records that duplicate existing table records on unique index values. Deleted indicates how many records were deleted from the table and replaced by input records, and Skipped indicates how many input records were ignored in favor of existing records.
  • Warnings is something of a catch-all that indicates the number of problems found while loading data values into columns. Either a value stores into a column properly, or it doesn't. In the latter case, the value ends up in MySQL as something different and MySQL counts it as a warning. (Storing a string abc into a numeric column results in a stored value of 0, for example.)

What do these values tell you? The Records value normally should match the number of lines in the input file. If it is different than the file's line count, that's a sign that MySQL is interpreting the file as having a format that differs from the format it actually has. In this case, you're likely also to see a high Warnings value, which indicates that many values had to be converted because they didn't match the expected data type. (The solution to this problem often is to specify the proper FIELDS and LINES clauses.) Otherwise, the values may not tell you a lot. You can't tell from these numbers which input records had problems or which columns were bad. There is some work being done for MySQL 4 to make additional warning information available. In the meantime, see Recipe 10.38 for a script that examines your datafile and attempts to pinpoint troublesome data values.

Using the mysql Client Program

Writing MySQL-Based Programs

Record Selection Techniques

Working with Strings

Working with Dates and Times

Sorting Query Results

Generating Summaries

Modifying Tables with ALTER TABLE

Obtaining and Using Metadata

Importing and Exporting Data

Generating and Using Sequences

Using Multiple Tables

Statistical Techniques

Handling Duplicates

Performing Transactions

Introduction to MySQL on the Web

Incorporating Query Resultsinto Web Pages

Processing Web Input with MySQL

Using MySQL-Based Web Session Management

Appendix A. Obtaining MySQL Software

Appendix B. JSP and Tomcat Primer

Appendix C. References

MySQL Cookbook
MySQL Cookbook
ISBN: 059652708X
EAN: 2147483647
Year: 2005
Pages: 412
Authors: Paul DuBois

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