What is SQL Loader
SQL LOADER is an Oracle utility used to load data into table given a datafile which has the records that need to be loaded. SQL*Loader takes data file, as well as a control file, to insert data into the table. When a Control file is executed, it can create Three (3) files called a
log file, bad file or reject file, discard file.
- Log file tells you the state of the tables and indexes and the number of logical records already read from the input datafile. This information can be used to resume the load where it left off.
- Bad file or reject file gives you the records that were rejected because of formatting errors or because they caused Oracle errors.
- Discard file specifies the records that do not meet any of the loading criteria like when any of the WHEN clauses specified in the control file. These records differ from rejected records.
What is Structure of the data file:
The data file can be in fixed record format or variable record format.
Fixed Record Format would look like the below. In this case you give a specific position where the Control file can expect a data field:
7369 SMITH CLERK 7902 12/17/1980 800
7499 ALLEN SALESMAN 7698 2/20/1981 1600
7521 WARD SALESMAN 7698 2/22/1981 1250
7566 JONES MANAGER 7839 4/2/1981 2975
7654 MARTIN SALESMAN 7698 9/28/1981 1250
7698 BLAKE MANAGER 7839 5/1/1981 2850
7782 CLARK MANAGER 7839 6/9/1981 2450
7788 SCOTT ANALYST 7566 12/9/1982 3000
7839 KING PRESIDENT 11/17/1981 5000
7844 TURNER SALESMAN 7698 9/8/1981 1500
7876 ADAMS CLERK 7788 1/12/1983 1100
7900 JAMES CLERK 7698 12/3/1981 950
7902 FORD ANALYST 7566 12/3/1981 3000
7934 MILLER CLERK 7782 1/23/1982 1300
Variable Record Format would like below where the data fields are separated by a delimiter.
Note: The Delimiter can be anything you like. In this case it is "|"
1196700|9|0|692.64
1378901|2|3900|488.62
1418700|2|2320|467.92
1418702|14|8740|4056.36
1499100|1|0|3.68
1632800|3|0|1866.66
1632900|1|70|12.64
1637600|50|0|755.5
Structure of a Control file:
Sample CTL file for loading a Variable record data file:
OPTIONS (SKIP = 1) --The first row in the data file is skipped without loading
LOAD DATA
INFILE '$FILE' -- Specify the data file path and name
APPEND -- type of loading (INSERT, APPEND, REPLACE, TRUNCATE
INTO TABLE "APPS"."BUDGET" -- the table to be loaded into
FIELDS TERMINATED BY '|' -- Specify the delimiter if variable format datafile
OPTIONALLY ENCLOSED BY '"' --the values of the data fields may be enclosed in "
TRAILING NULLCOLS -- columns that are not present in the record treated as null
(ITEM_NUMBER "TRIM(:ITEM_NUMBER)", -- Can use all SQL functions on columns
QTY DECIMAL EXTERNAL,
REVENUE DECIMAL EXTERNAL,
EXT_COST DECIMAL EXTERNAL TERMINATED BY WHITESPACE "(TRIM(:EXT_COST))" ,
MONTH "to_char(LAST_DAY(ADD_MONTHS(SYSDATE,-1)),'DD-MON-YY')" ,
DIVISION_CODE CONSTANT "AUD" -- Can specify constant value instead of
Getting value from datafile
)
OPTION statement precedes the LOAD DATA statement. The OPTIONS parameter allows you to specify runtime arguments in the control file, rather than on the command line. The following arguments can be specified using the OPTIONS parameter.
SKIP = n -- Number of logical records to skip (Default 0)
LOAD = n -- Number of logical records to load (Default all)
ERRORS = n -- Number of errors to allow (Default 50)
ROWS = n -- Number of rows in conventional path bind array or between direct path data saves (Default: Conventional Path 64, Direct path all)
BINDSIZE = n -- Size of conventional path bind array in bytes (System-dependent default)
SILENT = {FEEDBACK | ERRORS | DISCARDS | ALL} -- Suppress messages during run
(header, feedback, errors, discards, partitions, all)
DIRECT = {TRUE | FALSE} --Use direct path (Default FALSE)
PARALLEL = {TRUE | FALSE} -- Perform parallel load (Default FALSE)
LOAD DATA statement is required at the beginning of the control file.
INFILE: INFILE keyword is used to specify location of the datafile or datafiles.
INFILE * specifies that the data is found in the control file and not in an external file. INFILE '$FILE', can be used to send the filepath and filename as a parameter when registered as a concurrent program.
INFILE '/home/vision/kap/import2.csv' specifies the filepath and the filename.
Example where datafile is an external file:
LOAD DATA
INFILE '/home/vision/kap/import2.csv'
INTO TABLE kap_emp
FIELDS TERMINATED BY ","
( emp_num, emp_name, department_num, department_name )
Example where datafile is in the Control file:
LOAD DATA
INFILE *
INTO TABLE kap_emp
FIELDS TERMINATED BY ","
( emp_num, emp_name, department_num, department_name )
BEGINDATA
7369,SMITH,7902,Accounting
7499,ALLEN,7698,Sales
7521,WARD,7698,Accounting
7566,JONES,7839,Sales
7654,MARTIN,7698,Accounting
Example where file name and path is sent as a parameter when registered as a concurrent program
LOAD DATA
INFILE '$FILE'
INTO TABLE kap_emp
FIELDS TERMINATED BY ","
( emp_num, emp_name, department_num, department_name )
TYPE OF LOADING:
INSERT -- If the table you are loading is empty, INSERT can be used.
APPEND -- If data already exists in the table, SQL*Loader appends the new rows to it. If data doesn't already exist, the new rows are simply loaded.
REPLACE -- All rows in the table are deleted and the new data is loaded
TRUNCATE -- SQL*Loader uses the SQL TRUNCATE command.
INTO TABLE is required to identify the table to be loaded into. In the above example INTO TABLE "APPS"."BUDGET", APPS refers to the Schema and BUDGET is the Table name.
FIELDS TERMINATED BY specifies how the data fields are terminated in the datafile.(If the file is Comma delimited or Pipe delimited etc)
OPTIONALLY ENCLOSED BY '"' specifies that data fields may also be enclosed by quotation marks.
TRAILING NULLCOLS clause tells SQL*Loader to treat any relatively positioned columns that are not present in the record as null columns.
How to Loading a fixed format data file:
LOAD DATA
INFILE 'sample.dat'
INTO TABLE emp
( empno POSITION(01:04) INTEGER EXTERNAL,
ename POSITION(06:15) CHAR,
job POSITION(17:25) CHAR,
mgr POSITION(27:30) INTEGER EXTERNAL,
sal POSITION(32:39) DECIMAL EXTERNAL,
comm POSITION(41:48) DECIMAL EXTERNAL,
deptno POSITION(50:51) INTEGER EXTERNAL)
What are Steps to Run the SQL* LOADER from UNIX:
At the prompt, invoke SQL*Loader as follows:
sqlldr USERID=scott/tiger CONTROL= LOG=
name>
SQL*Loader loads the tables, creates the log file, and returns you to the system prompt. You can check the log file to see the results of running the case study.
How to Register as concurrent Program:
Place the Control file in $CUSTOM_TOP/bin.
Define the Executable. Give the Execution Method as SQL*LOADER.
Define the Program. Add the Parameter for FILENAME.
How to Skip columns:
You can skip columns using the 'FILLER' option.
Load Data
--
--
--
TRAILING NULLCOLS
(
name Filler,
Empno ,
sal
)
here the column name will be skipped.
