You can specify the byte offset, the length of the data field, or both. This way each field starts a specified number of bytes from where the last one ended and continues for a specified length.
Length-value data types can be used. In this case, the first n number of bytes of the data field contain information about how long the rest of the data field is. Therefore, the processing overhead of dealing with records is avoided. This type of organization of data is ideal for LOB loading.
For example, suppose you have a table that stores employee names, IDs, and their resumes. You can use XML columns to hold data that models structured and semistructured data. Such data can be quite lengthy. Secondary data files SDFs are similar in concept to primary data files.
As with primary data files, SDFs are a collection of records, and each record is made up of fields. The SDFs are specified as needed for a control file field. You can enter a value for the SDF parameter either by using the file specification string, or by using a FILLER field that is mapped to a data field containing one or more file specification strings. During a conventional path load, data fields in the data file are converted into columns in the database direct path loads are conceptually similar, but the implementation is different.
When the bind array is full, the data is transmitted to the database. Oracle Database uses the data type of the column to convert the data into its final, stored form. Keep in mind the distinction between a field in a data file and a column in the database.
Rejected records are placed in a bad file, and discarded records are placed in a discard file. A rejected record has the same name as the data file, with a. There can be several causes for rejections. Rejected records are placed in the bad file. If the database determines that the row is valid, then the row is inserted into the table. The row may be invalid, for example, because a key is not unique, because a required field is null, or because the field contains invalid data for the Oracle data type.
A discard file is created only when it is needed, and only if you have specified that a discard file should be enabled. The discard file contains records that were filtered out of the load because they did not match any record-selection criteria specified in the control file.
Because the discard file contains record filtered out of the load, the contents of the discard file are records that were not inserted into any table in the database. You can specify the maximum number of such records that the discard file can accept.
Data written to any database table is not written to the discard file. The log file contains a detailed summary of the load, including a description of any errors that occurred during the load.
When the bind array is full or no more data is left to read , an array insert operation is performed. This is not possible because the LOB contents will not have been loaded at the time the trigger fires. Data Loading Methods. Bind Arrays and Conventional Path Loads. A direct path load parses the input records according to the field specifications, converts the input field data to the column data type, and builds a column array.
The column array is passed to a block formatter, which creates data blocks in Oracle database block format. The newly formatted database blocks are written directly to the database, bypassing much of the data processing that normally takes place.
Direct path load is much faster than conventional path load, but entails several restrictions. A parallel direct path load allows multiple direct path load sessions to concurrently load the same data segments allows intrasegment parallelism.
Parallel Data Loading Models. Direct Path Load. External tables are defined as tables that do not reside in the database, and can be in any format for which an access driver is provided. By providing the database with metadata describing an external table, the database is able to expose the data in the external table as if it were data residing in a regular database table. An external table load creates an external table for data that is contained in an external data file.
The advantages of using external table loads over conventional path and direct path loads are as follows:. If a data file is big enough, then an external table load attempts to load that file in parallel.
With external table loads, there is only one bad file and one discard file for all input data files. If parallel access drivers are used for the external table load, then each access driver has its own bad file and discard file. This section provides a description of unsupported syntax and data types with external table loads. If a primary data file uses a Unicode character set UTF8 or UTF16 , and it also contains a byte-order mark BOM , then the byte-order mark is written at the beginning of the corresponding bad and discard files.
With external table loads, the byte-order mark is not written at the beginning of the bad and discard files. For fields in external tables, the database settings of the NLS parameters determine the default character set, date masks, and decimal separator.
For example. In external tables, the use of the backslash escape character within a string raises an error. The workaround is to use double quotation marks to identify a single quotation mark as the enclosure character. In the following example, you have a table T into which you are loading data:. You have a data file that you want to load to this table, named file1. The contents are as follows:. Upload the file file1. The easiest way to upload file to object storage is to upload the file from the Oracle Cloud console:.
This example shows the use of a federated user account myfedcredential. The password is automatically generated, as described in Oracle Cloud Infrastructure Documentation. You can bulk-load the column, row, LOB, and JSON database objects that you need to model real-world entities, such as customers and purchase orders.
When a column of a table is of some object type, the objects in that column are referred to as column objects. Conceptually such objects are stored in their entirety in a single column position in a row. These objects are stored in tables, known as object tables, that have columns corresponding to the attributes of the object.
Columns in other tables can refer to these objects by using the OIDs. A nested table is a table that appears as a column in another table. All operations that can be performed on other tables can also be performed on nested tables. An array is an ordered set of built-in types or objects, called elements. Each array element is of the same type and has an index, which is a number corresponding to the element's position in the VARRAY.
LOBs can have an actual value, they can be null , or they can be "empty. A partitioned object in an Oracle database is a table or index consisting of partitions pieces that have been grouped, typically by common logical attributes. For example, sales data for the year might be partitioned by month. The data for each month is stored in a separate partition of the sales table.
Each partition is stored in a separate segment of the database and can have different physical attributes. Oracle provides a direct path load API for application developers. In some case studies, additional columns have been added. The case studies are numbered 1 through 11, starting with the simplest scenario and progressing in complexity.
Case Study 1: Loading Variable-Length Data - Loads stream format records in which the fields are terminated by commas and may be enclosed by quotation marks. The data is found at the end of the control file. Case Study 3: Loading a Delimited, Free-Format File - Loads data from stream format records with delimited fields and sequence numbers. Case Study 4: Loading Combined Physical Records - Combines multiple physical records into one logical record corresponding to one database row.
This case study uses character-length semantics. These files are installed when you install Oracle Database. If the sample data for the case study is contained within the control file, then there will be no. Case study 2 does not require any special set up, so there is no. Case study 7 requires that you run both a starting setup script and an ending cleanup script. For example, to execute the SQL script for case study 1, enter the following:.
Be sure to read the control file for any notes that are specific to the particular case study you are executing. This is because the log file for each case study is produced when you execute the case study, provided that you use the LOG parameter.
If you do not wish to produce a log file, omit the LOG parameter from the command line. This is done, as follows:. For example, if the table emp was loaded, enter:. Load data from multiple datafiles during the same load session. Load data into multiple tables during the same load session.
Specify the character set of the data. Selectively load data you can load records based on the records' values. Manipulate the data before loading it, using SQL functions. Generate unique sequential key values in specified columns. Use the operating system's file system to access the datafiles.
Load data from disk, tape, or named pipe. Generate sophisticated error reports, which greatly aid troubleshooting. Load arbitrarily complex object-relational data. Use secondary datafiles for loading LOBs and collections. In situations where you always use the same parameters for which the values seldom change, it can be more efficient to specify parameters using the following methods, rather than on the command line: Parameters can be grouped together in a parameter file.
Although not precisely defined, a control file can be said to have three sections. The third section is optional and, if present, contains input data. Some control file syntax considerations to keep in mind are: The syntax is free-format statements can extend over multiple lines.
See Also: Chapter 8 for details about control file syntax and semantics. Fixed Record Format A file is in fixed record format when all records in a datafile are the same byte length.
Variable Record Format A file is in variable record format when the length of each record in a character field is included at the beginning of each record in the datafile.
Combine physical records into logical records while a certain condition is true. Data Fields Once a logical record is formed, field setting on the logical record is done. This mapping takes the following forms: The byte position of the data field's beginning, end, or both, can be specified. Data Conversion and Datatype Specification During a conventional path load, data fields in the datafile are converted into columns in the database direct path loads are conceptually similar, but the implementation is different.
Discarded and Rejected Records Records read from the input file might not be inserted into the database. What do you call a "type of flat files"?
Bohemian, technically, the answer to a question worded like "How many Add a comment. Active Oldest Votes. Oracle supports the below types of flat files. When using flat files as sources : You can read from character data set files or binary flat files. You can read from delimited files, fixed length files, or XML files.
You can also add flat file operators in code template based mappings and leverage code templates that are specifically constructed for files or the generic SQL code templates which leverages a built-in JDBC driver for files. When using flat files as targets : You can use only character data set files. Binary flat files are not supported as targets. You can write to delimited files and fixed length files. You can use flat file operators to write data to flat files.
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