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SQL Anywhere 11.0.1 » SQL Anywhere Server - SQL Usage » Remote Data and Bulk Operations » Importing and exporting data » Importing data


Import data with the LOAD TABLE statement

Use the LOAD TABLE statement to import data residing on a database server or a client computer into an existing table in text/ASCII format.

You can also use the LOAD TABLE statement to import data from a column from another table, or from a value expression (for example, from the results of a function or system procedure).

The LOAD TABLE statement adds rows into a table; it doesn't replace them.

Loading data using the LOAD TABLE statement (without the WITH ROW LOGGING and WITH CONTENT LOGGING options) is considerably faster than using the INPUT statement.

Triggers do not fire for data loaded using the LOAD TABLE statement.

Considerations for materialized views

For immediate views, an error is returned when you attempt to bulk load data into an underlying table. You must truncate the data in the view first, and then perform the bulk load operation.

For manual views, you can bulk load data into an underlying table; however, the data in the view becomes stale until the next refresh.

Consider truncating data in dependent materialized views before attempting a bulk load operation such as LOAD TABLE on a table. After you have loaded the data, refresh the view. See TRUNCATE statement, and REFRESH MATERIALIZED VIEW statement.

Considerations for text indexes

For immediate text indexes, updating the text index after performing a bulk load operation such as LOAD TABLE on the underlying table can take a while even though the update is automatic. For manual text indexes, even a refresh can take a while.

Consider dropping dependent text indexes before performing a bulk load operation such as LOAD TABLE on a table. After you have loaded the data, recreate the text index. See DROP TEXT INDEX statement, and CREATE TEXT INDEX statement.

Considerations for database recovery and synchronization

By default, when data is loaded from a file (for example, LOAD TABLE table-name FROM filename;), only the LOAD TABLE statement is recorded in the transaction log, not the actual rows of data that are being loaded. This presents a problem when trying to recover the database using the transaction log if the original load file has been changed, moved, or deleted. It also means that databases involved in synchronization or replication do not get the new data.

To address the recovery and synchronization considerations, two logging options are available for the LOAD TABLE statement: WITH ROW LOGGING, which creates INSERT statements in the transaction log for every row that is loaded, and WITH CONTENT LOGGING, which groups the loaded rows into chunks and records the chunks in the transaction log. These options allow a load operation to be repeated, even when the source of the loaded data is no longer available. See LOAD TABLE statement.

Considerations for database mirroring

If your database is involved in mirroring, use the LOAD TABLE statement carefully. For example, if you are loading data from a file, consider whether the file will be available for loading on the mirror server, or whether data in the source you are loading from will change by the time the mirror database processes the load. If either of these risks exists, consider specifying either WITH ROW LOGGING or WITH CONTENT LOGGING as the logging level in the LOAD TABLE statement. That way, the data loaded into the mirror database is identical to what was loaded in the mirrored database. See LOAD TABLE statement.

See also