Handle Null Values In Sql Loader [ TRENDING – 2024 ]
A keyword used with NULLIF to identify fields containing only whitespace.
LOAD DATA INFILE 'data.csv' INTO TABLE employees FIELDS TERMINATED BY ',' TRAILING NULLCOLS ( emp_id, emp_name, commission_pct -- If this is missing in the file, it becomes NULL ) Use code with caution. Copied to clipboard 5. Using SQL Functions Handle Null Values In Sql Loader
If your data file has records where the last few columns are often empty, SQL Loader might throw an error because it expects more delimiters. Use the TRAILING NULLCOLS clause at the table level to tell SQL Loader to treat any missing relative fields at the end of a record as nulls. A keyword used with NULLIF to identify fields
By default, if a field in the data file is empty (contains no data between delimiters), SQL*Loader attempts to load it as a . However, if the column in the database has a NOT NULL constraint, the record will be rejected and moved to the .bad file. 2. Using the NULLIF Clause Using SQL Functions If your data file has
You can also use Oracle SQL functions within the control file to handle null logic during the load process. This is helpful for replacing nulls with a specific value (like NVL ). column_name "NVL(:column_name, 'Unknown')" Use code with caution. Copied to clipboard Summary of Key Commands NULLIF Sets column to NULL if a specific condition is met. DEFAULTIF Uses the database's default value if a condition is met. TRAILING NULLCOLS Prevents errors when the last columns in a row are missing. BLANKS
Handling null values in SQL*Loader involves managing how data from your flat file is interpreted and loaded into Oracle database tables. You can control this behavior using specific clauses in your control file ( .ctl ). 1. Default Behavior
: Useful for fixed-width files or fields that might contain spaces. column_name NULLIF (column_name = BLANKS) Use code with caution. Copied to clipboard 3. Using the DEFAULTIF Clause
