The Ultimate Guide to High Availability with MariaDB

LOAD XML

Syntax

LOAD XML [LOW_PRIORITY | CONCURRENT] [LOCAL] INFILE 'file_name'
    [REPLACE | IGNORE]
    INTO TABLE [db_name.]tbl_name
    [CHARACTER SET charset_name]
    [ROWS IDENTIFIED BY '<tagname>']
    [IGNORE number {LINES | ROWS}]
    [(column_or_user_var,...)]
    [SET col_name = expr,...]

Description

The LOAD XML statement reads data from an XML file into a table. The file_name must be given as a literal string. The tagname in the optional ROWS IDENTIFIED BY clause must also be given as a literal string, and must be surrounded by angle brackets (< and >).

LOAD XML acts as the complement of running the mariadb client in XML output mode (that is, starting the client with the --xml option). To write data from a table to an XML file, use a command such as the following one from the system shell:

shell> mariadb --xml -e 'SELECT * FROM mytable' > file.xml

To read the file back into a table, use LOAD XML INFILE. By default, the <row> element is considered to be the equivalent of a database table row; this can be changed using the ROWS IDENTIFIED BY clause.

This statement supports three different XML formats:

  • Column names as attributes and column values as attribute values: 
<row column1="value1" column2="value2" .../>
  • Column names as tags and column values as the content of these tags: 
<row>
  <column1>value1</column1>
  <column2>value2</column2>
</row>
  • Column names are the name attributes of <field> tags, and values are the contents of these tags: 
<row>
  <field name='column1'>value1</field>
  <field name='column2'>value2</field>
</row>

This is the format used by other tools, such as mariadb-dump.

All 3 formats can be used in the same XML file; the import routine automatically detects the format for each row and interprets it correctly. Tags are matched based on the tag or attribute name and the column name.

The following clauses work essentially the same way for LOAD XML as they do for LOAD DATA:

  • LOW_PRIORITY or CONCURRENT
  • LOCAL
  • REPLACE or IGNORE
  • CHARACTER SET
  • (column_or_user_var,...)
  • SET

See LOAD DATA for more information about these clauses.

The IGNORE number LINES or IGNORE number ROWS clause causes the first number rows in the XML file to be skipped. It is analogous to the LOAD DATA statement's IGNORE ... LINES clause.

If the LOW_PRIORITY keyword is used, insertions are delayed until no other clients are reading from the table. The CONCURRENT keyword allows the use of concurrent inserts. These clauses cannot be specified together.

This statement activates INSERT triggers.

See Also

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