DBE_FILE

Precautions

• DBE_FILE requires that files opened using DBE_FILE.FOPEN be encoded using the database character set. If the opened files are not encoded using the expected character set, an encoding verification error occurs when DBE_FILE.READ_LINE is used to read files. DBE_FILE requires that files opened using DBE_FILE.FOPEN_NCHAR be encoded using the UTF-8 character set. If the opened files are not encoded using the expected character set, an encoding verification error occurs when DBE_FILE.READ_LINE_NCHAR is used to read files.
• When DBE_OUTPUT.PUT_LINE is used to print the result obtained by the DBE_FILE.READ_LINE_NCHAR API, ensure that the UTF-8 character set encoding can be converted to the current database character set encoding. If the preceding conditions are met, the result can be properly output. DBE_OUTPUT.PRINT_LINE does not support this function.
• DBE_FILE requires that the character set encoding of the client be the same as that of the database.
• If the database character set encoding format is ASCII and the client character set encoding format is Chinese, when the client calls DBE_FILE.WRITE_NCHAR or DBE_FILE.WRITE_LINE_NCHAR to write Chinese content, the written content may be in UTF-8 encoding format. An error may be reported when the DBE_FILE.READ_LINE_NCHAR is used.

Data Types

• DBE_FILE.FILE_TYPE

  Defines the representation of files in the DBE_FILE package. The fields in DBE_FILE.FILE_TYPE are private fields of the DBE_FILE package. Do not change the field value of the type defined in DBE_FILE.FILE_TYPE.

  1 2 3 4 5

  CREATE TYPE DBE_FILE.FILE_TYPE AS( id INTEGER, datatype INTEGER, byte_mode BOOLEAN );

  Table 1 DBE_FILE.FILE_TYPE columns

  Parameter	Description
  id	File handle
  datatype	File data type (CHAR, NCHAR, or binary). Currently, only CHAR and NCHAR files are supported. For a CHAR file, 1 is returned. For an NCHAR file, 2 is returned.
  byte_mode	Indicates that the file is opened in binary mode (TRUE) or text mode (FALSE).

API Description

Table 2 lists all APIs supported by the DBE_FILE package.

• DBE_FILE.OPEN/DBE_FILE.FOPEN

  Opens a file. You can specify the maximum line size. A maximum of 50 files can be opened in a session. This function returns a file handle of the INTEGER type. The function of DBE_FILE.FOPEN is similar to that of DBE_FILE.OPEN. It returns an object of the type defined in DBE_FILE.FILE_TYPE.

  The prototype of the DBE_FILE.OPEN function is as follows:

  1 2 3 4 5 6 7 8 9 10 11 12 13

  DBE_FILE.OPEN( dir IN TEXT, file_name IN TEXT, open_mode IN TEXT, max_line_size IN INTEGER DEFAULT 1024) RETURN INTEGER; DBE_FILE.FOPEN( dir IN TEXT, file_name IN TEXT, open_mode IN TEXT, max_line_size IN INTEGER DEFAULT 1024) RETURN DBE_FILE.FILE_TYPE;

  Table 3 DBE_FILE.OPEN/DBE_FILE.FOPEN parameters

  Parameter	Description
  dir	Directory of a file. It is a string, indicating an object name. NOTE: Location of the file directory, which needs to be added to system catalog PG_DIRECTORY. If the input path does not match the path in PG_DIRECTORY, an error indicating that the path does not exist is reported. When the GUC parameter safe_data_path is enabled, you can only use an advanced package to read and write files in the file path specified by safe_data_path.
  file_name	File name with an extension (file type), excluding the path name. A path contained in a file name is ignored in the OPEN function. In Unix, the file name cannot end with the combination of a slash and a dot (/.).
  open_mode	Open mode of a specified file, including r (read text), w (write text), a (append text), rb (read byte), wb (write byte), and ab (append byte). NOTE: For the write operation, the system checks the file type. If the ELF file is written, an error is reported and the system exits.
  max_line_size	Maximum number of characters in each line, including newline characters. The minimum value is 1 and the maximum is 32767. If this parameter is not specified, the default value 1024 is used.

• DBE_FILE.IS_CLOSE

  Checks whether a file is closed. A Boolean value is returned. If an invalid file handle is detected, the INVALID_FILEHANDLE exception is thrown.

  The prototype of the DBE_FILE.IS_CLOSE function is as follows:

  1 2 3 4 5 6 7

  DBE_FILE.IS_CLOSE( file IN INTEGER) RETURN BOOLEAN; DBE_FILE.IS_CLOSE( file IN DBE_FILE.FILE_TYPE) RETURN BOOLEAN;

  Table 4 DBE_FILE.IS_CLOSE parameters

  Parameter	Description
  file	File handle or DBE_FILE.FILE_TYPE object to be checked

• DBE_FILE.IS_OPEN

  Checks whether a file is opened. A Boolean value is returned. If an invalid file handle is detected, the INVALID_FILEHANDLE exception is thrown.

  The prototype of the DBE_FILE.IS_OPEN function is as follows:

  1 2 3 4 5 6 7

  DBE_FILE.IS_OPEN( file IN INTEGER) RETURN BOOLEAN; DBE_FILE.IS_OPEN( file IN DBE_FILE.FILE_TYPE) RETURN BOOLEAN;

  Table 5 DBE_FILE.IS_OPEN parameters

  Parameter	Description
  file	File handle or DBE_FILE.FILE_TYPE object to be checked

• DBE_FILE.READ_LINE

  Reads data from an open file and stores the read result to the buffer. It reads data to the end of each line excluding the line terminator, to the end of the file, or to the size specified by the len parameter. The length of the data to be read cannot exceed the value of max_line_size specified when the file is opened.

  The prototype of the DBE_FILE.READ_LINE stored procedure is as follows:

  1 2 3 4 5 6 7 8 9

  DBE_FILE.READ_LINE( file IN INTEGER, buffer OUT TEXT, len IN INTEGER DEFAULT NULL); DBE_FILE.READ_LINE( file IN DBE_FILE.FILE_TYPE, buffer OUT TEXT, len IN INTEGER DEFAULT NULL);

  Table 6 DBE_FILE.READ_LINE parameters

  Parameter	Description
  file	File handle opened using OPEN or object of the DBE_FILE.FILE_TYPE type opened using FOPEN. The file must be opened in read mode. Otherwise, the INVALID_OPERATION exception is thrown.
  buffer	Buffer for receiving data.
  len	Number of bytes read from the file. The default value is NULL. If the default value NULL is used, max_line_size is used to specify the line size.

• DBE_FILE.WRITE

  Writes data in the buffer to a file. The file must be opened in write mode. This operation does not write a line terminator, and the return value is always TRUE.

  The prototype of the DBE_FILE.WRITE function is as follows:

  1 2 3 4 5 6 7 8 9

  DBE_FILE.WRITE( file IN INTEGER, buffer IN TEXT) RETURN BOOLEAN; DBE_FILE.WRITE( file IN DBE_FILE.FILE_TYPE, buffer IN TEXT) RETURN VOID;

  Table 7 DBE_FILE.WRITE parameters

  Parameter	Description
  file	File handle opened using OPEN or object of the DBE_FILE.FILE_TYPE type opened using FOPEN. The file must be opened in write mode. This operation does not write line terminators.
  buffer	Text data to be written to the file. The accumulated write length of each line cannot be greater than or equal to the value of max_line_size specified when OPEN or FOPEN is used. Otherwise, an error is reported when the file is refreshed. NOTE: For the write operation, the system checks the file type. If the ELF file is written, an error is reported and the system exits.

• DBE_FILE.NEW_LINE

  Writes one or more line terminators to an open file. The line terminators are related to the platform used, and the return value is always TRUE.

  The prototype of the DBE_FILE.NEW_LINE function is as follows:

  1 2 3 4 5 6 7 8 9

  DBE_FILE.NEW_LINE( file IN INTEGER, line_nums IN INTEGER DEFAULT 1) RETURN BOOLEAN; DBE_FILE.NEW_LINE( file IN DBE_FILE.FILE_TYPE, line_nums IN INTEGER DEFAULT 1) RETURN VOID;

  Table 8 DBE_FILE.NEW_LINE parameters

  Parameter	Description
  file	File handle opened using OPEN or object of the DBE_FILE.FILE_TYPE type opened using FOPEN.
  line_nums	Number of line terminators written to a file.

• DBE_FILE.WRITE_LINE

  Writes data in the buffer to a file. The file must be opened in write mode. This operation automatically appends line terminators, and the return value is always TRUE.

  The prototype of the DBE_FILE.WRITE_LINE function is as follows:

  1 2 3 4 5 6 7 8 9 10 11

  DBE_FILE.WRITE_LINE( file IN INTEGER, buffer IN TEXT, flush IN BOOLEAN DEFAULT FALSE) RETURN BOOLEAN; DBE_FILE.WRITE_LINE( file IN DBE_FILE.FILE_TYPE, buffer IN TEXT, flush IN BOOLEAN DEFAULT FALSE) RETURN VOID;

  Table 9 DBE_FILE.WRITE_LINE parameters

  Parameter	Description
  file	File handle opened using OPEN or object of the DBE_FILE.FILE_TYPE type opened using FOPEN.
  buffer	Text data to be written to the file. The length of each line (including the newline character) cannot be greater than the value of max_line_size specified when OPEN or FOPEN is executed or the default value. Otherwise, an error is reported when the file is refreshed. NOTE: For the write operation, the system checks the file type. If the ELF file is written, an error is reported and the system exits.
  flush	Whether to flush data to disks after WRITE_LINE. The default value is FALSE.

• DBE_FILE.FORMAT_WRITE

  Writes formatted data to an open file. It is a DBE_FILE.WRITE API that allows formatting. The return value is always TRUE.

  The prototype of the DBE_FILE.FORMAT_WRITE function is as follows:

  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

  DBE_FILE.FORMAT_WRITE( file IN INTEGER, format IN TEXT, arg1 IN TEXT DEFAULT NULL, . . . arg6 IN TEXT DEFAULT NULL) RETURN BOOLEAN; DBE_FILE.FORMAT_WRITE( file IN DBE_FILE.FILE_TYPE, format IN TEXT, arg1 IN TEXT DEFAULT NULL, . . . arg6 IN TEXT DEFAULT NULL) RETURN VOID;

  Table 10 DBE_FILE.FORMAT_WRITE parameters

  Parameter	Description
  file	File handle opened using OPEN or object of the DBE_FILE.FILE_TYPE type opened using FOPEN.
  format	Formatted string, containing the text and format characters \n and %s.
  [arg1. . .arg6]	Six optional parameters. The parameters and the positions of characters to be formatted are in one-to-one correspondence. If the parameter corresponding to a character to be formatted is not provided, an empty string is used to replace %s.

• DBE_FILE.GET_RAW

  Reads RAW data from an open file, stores the read result in the buffer, and returns the result from r.

  The prototype of the DBE_FILE.GET_RAW stored procedure is as follows:

  1 2 3 4 5 6 7 8 9

  DBE_FILE.GET_RAW( file IN INTEGER, r OUT RAW, length IN INTEGER DEFAULT NULL); DBE_FILE.GET_RAW( file IN DBE_FILE.FILE_TYPE, r OUT RAW, length IN INTEGER DEFAULT NULL);

  Table 11 DBE_FILE.GET_RAW parameters

  Parameter	Description
  file	File handle opened using OPEN or object of the DBE_FILE.FILE_TYPE type opened using FOPEN.
  r	Buffer for receiving RAW data.
  length	Number of bytes read from the file. The default value is NULL. If the value is NULL, the maximum length of the RAW type is used to specify the size.

• DBE_FILE.PUT_RAW

  Writes RAW data to a file. The return value is always TRUE.

  The prototype of the DBE_FILE.PUT_RAW function is as follows:

  1 2 3 4 5 6 7 8 9 10 11

  DBE_FILE.PUT_RAW ( file IN INTEGER, r IN RAW, flush IN BOOLEAN DEFAULT FALSE) RETURN BOOLEAN; DBE_FILE.PUT_RAW ( file IN DBE_FILE.FILE_TYPE, r IN RAW, flush IN BOOLEAN DEFAULT FALSE) RETURN VOID;

  Table 12 DBE_FILE.PUT_RAW parameters

  Parameter	Description
  file	File handle opened using OPEN or object of the DBE_FILE.FILE_TYPE type opened using FOPEN.
  r	RAW data to be written to a file. NOTE: For the write operation, the system checks the file type. If the ELF file is written, an error is reported and the system exits.
  flush	Whether to flush data to disks after PUT_RAW. The default value is FALSE.

• DBE_FILE.FLUSH

  Writes cached data to a physical file. The cached data must have a line terminator.

  The prototype of the DBE_FILE.FLUSH function is as follows:

  1 2 3 4 5 6 7

  DBE_FILE.FLUSH( file IN INTEGER) RETURN VOID; DBE_FILE.FLUSH( file IN DBE_FILE.FILE_TYPE) RETURN VOID;

  Table 13 DBE_FILE.FLUSH parameters

  Parameter	Description
  file	File handle opened using OPEN or object of the DBE_FILE.FILE_TYPE type opened using FOPEN.

• DBE_FILE.CLOSE

  Closes an open file. When this function is called, if there is cached data to be written, exception information may be received and the return value is always TRUE.

  The prototype of the DBE_FILE.CLOSE function is as follows:

  1 2 3 4 5 6 7

  DBE_FILE.CLOSE( file IN INTEGER) RETURN BOOLEAN; DBE_FILE.CLOSE( file IN DBE_FILE.FILE_TYPE) RETURN BOOLEAN;

  Table 14 DBE_FILE.CLOSE parameters

  Parameter	Description
  file	File handle opened using OPEN or object of the DBE_FILE.FILE_TYPE type opened using FOPEN.

• DBE_FILE.CLOSE_ALL

  Closes all file handles opened in a session. This function can be used for emergency cleanup.

  The prototype of the DBE_FILE.CLOSE_ALL function is as follows:

  1 2	DBE_FILE.CLOSE_ALL() RETRUN VOID;

  Table 15 DBE_FILE.CLOSE_ALL parameters

  Parameter	Description
  None	None

• DBE_FILE.REMOVE

  Deletes a disk file. To use this function, you must have the required permission.

  The prototype of the DBE_FILE.REMOVE function is as follows:

  1 2 3 4

  DBE_FILE.REMOVE( dir IN TEXT, file_name IN TEXT) RETURN VOID;

  Table 16 DBE_FILE.REMOVE parameters

  Parameter	Description
  dir	Directory of a file. It is a string, indicating an object name. NOTE: Location of the file directory, which needs to be added to system catalog PG_DIRECTORY. If the input path does not match the path in PG_DIRECTORY, an error indicating that the path does not exist is reported. When the GUC parameter safe_data_path is enabled, you can only use an advanced package to operate files in the file path specified by safe_data_path.
  file_name	File name.

• DBE_FILE.RENAME

  Renames a disk file. This function is similar to the mv command of Unix.

  The prototype of the DBE_FILE.RENAME function is as follows:

  1 2 3 4 5 6 7

  DBE_FILE.RENAME( src_dir IN TEXT, src_file_name IN TEXT, dest_dir IN TEXT, dest_file_name IN TEXT, overwrite IN BOOLEAN DEFAULT FALSE) RETURN VOID;

  Table 17 DBE_FILE.RENAME parameters

  Parameter	Description
  src_dir	Directory of the original file (case-sensitive) NOTE: Location of the file directory, which needs to be added to system catalog PG_DIRECTORY. If the input path does not match the path in PG_DIRECTORY, an error indicating that the path does not exist is reported. When the GUC parameter safe_data_path is enabled, you can only use an advanced package to operate files in the file path specified by safe_data_path.
  src_file_name	Original file to be renamed
  dest_dir	Target directory (case-sensitive). NOTE: Location of the file directory, which needs to be added to system catalog PG_DIRECTORY. If the input path does not match the path in PG_DIRECTORY, an error indicating that the path does not exist is reported. When the GUC parameter safe_data_path is enabled, you can only use an advanced package to operate files in the file path specified by safe_data_path.
  dest_file_name	New file name
  overwrite	Whether to overwrite the file. The default value is FALSE. If a file with the same name exists in the target directory, the file will not be overwritten.

• DBE_FILE.COPY

  Copies data in a continuous area to a new file. If start_line and end_line are omitted, the entire file is copied.

  The prototype of the DBE_FILE.COPY function is as follows:

  1 2 3 4 5 6 7 8

  DBE_FILE.COPY( src_dir IN TEXT, src_file_name IN TEXT, dest_dir IN TEXT, dest_file_name IN TEXT, start_line IN INTEGER DEFAULT 1, end_line IN INTEGER DEFAULT NULL) RETURN VOID;

  Table 18 DBE_FILE.COPY parameters

  Parameter	Description
  src_dir	Directory of the original file NOTE: Location of the file directory, which needs to be added to system catalog PG_DIRECTORY. If the input path does not match the path in PG_DIRECTORY, an error indicating that the path does not exist is reported. When the GUC parameter safe_data_path is enabled, you can only use an advanced package to operate files in the file path specified by safe_data_path.
  src_file_name	Original file
  dest_dir	Directory of the destination file NOTE: Location of the file directory, which needs to be added to system catalog PG_DIRECTORY. If the input path does not match the path in PG_DIRECTORY, an error indicating that the path does not exist is reported. When the GUC parameter safe_data_path is enabled, you can only use an advanced package to operate files in the file path specified by safe_data_path.
  dest_file_name	Target file NOTE: For the write operation, the system checks the file type. If the ELF file is written, an error is reported and the system exits.
  start_line	Number of the line where the copy starts. The default value is 1.
  end_line	Number of the line where the copy ends. The default value is NULL, indicating the end of the file.

• DBE_FILE.GET_ATTR

  Reads and returns the attributes of a disk file.

  The prototype of the DBE_FILE.GET_ATTR stored procedure is as follows:

  1 2 3 4 5 6

  DBE_FILE.GET_ATTR( location IN TEXT, filename IN TEXT, fexists OUT BOOLEAN, file_length OUT BIGINT, block_size OUT INTEGER);

  Table 19 DBE_FILE.GET_ATTR parameters

  Parameter	Description
  location	File directory NOTE: Location of the file directory, which needs to be added to system catalog PG_DIRECTORY. If the input path does not match the path in PG_DIRECTORY, an error indicating that the path does not exist is reported. When the GUC parameter safe_data_path is enabled, you can only use an advanced package to operate files in the file path specified by safe_data_path.
  filename	File name.
  fexists	Whether the file exists.
  file_length	File length (unit: byte). If the file does not exist, NULL is returned.
  block_size	Block size of the file system (unit: byte). If the file does not exist, NULL is returned.

• DBE_FILE.SEEK

  Adjusts the position of a file pointer forward or backward based on the specified number of bytes.

  The prototype of the DBE_FILE.SEEK function is as follows:

  1 2 3 4 5 6 7 8 9 10 11

  DBE_FILE.SEEK( file IN INTEGER, absolute_start IN BIGINT DEFAULT NULL, relative_start IN BIGINT DEFAULT NULL) RETURN VOID; DBE_FILE.SEEK( file IN DBE_FILE.FILE_TYPE, absolute_start IN BIGINT DEFAULT NULL, relative_start IN BIGINT DEFAULT NULL) RETURN VOID;

  Table 20 DBE_FILE.SEEK parameters

  Parameter	Description
  file	File handle opened using OPEN or object of the DBE_FILE.FILE_TYPE type opened using FOPEN.
  absolute_start	Absolute offset of a file. The default value is NULL.
  relative_start	Relative offset of a file. A positive number indicates forward offset and a negative number indicates backward offset. The default value is NULL. If both absolute_start and this parameter are specified, the absolute_start parameter is used.

• DBE_FILE.GET_POS

  Returns the current offset of the file in bytes.

  The prototype of the DBE_FILE.FGETPOS function is as follows:

  1 2 3 4 5 6 7

  DBE_FILE.GET_POS( file IN INTEGER) RETURN BIGINT; DBE_FILE.GET_POS( file IN DBE_FILE.FILE_TYPE) RETURN BIGINT;

  Table 21 DBE_FILE.GET_POS parameters

  Parameter	Description
  file	File handle opened using OPEN or object of the DBE_FILE.FILE_TYPE type opened using FOPEN.

• DBE_FILE.FOPEN_NCHAR

  Opens a file. You can specify the maximum line size. A maximum of 50 files can be opened in a session. This function returns a file handle of the DBE_FILE.FILE_TYPE type. This function opens a file in national character set mode for input or output.

  The prototype of the DBE_FILE.FOPEN_NCHAR function is as follows:

  1 2 3 4 5 6

  DBE_FILE.FOPEN_NCHAR( dir IN TEXT, file_name IN TEXT, open_mode IN TEXT, max_line_size IN INTEGER DEFAULT 1024) RETURN DBE_FILE.FILE_TYPE;

  Table 22 DBE_FILE.FOPEN_NCHAR parameters

  Parameter	Description
  dir	Directory of a file. It is a string, indicating an object name. NOTE: Location of the file directory, which needs to be added to system catalog PG_DIRECTORY. If the input path does not match the path in PG_DIRECTORY, an error indicating that the path does not exist is reported. When the GUC parameter safe_data_path is enabled, you can only use an advanced package to read and write files in the file path specified by safe_data_path.
  file_name	File name with an extension (file type), excluding the path name. A path contained in a file name is ignored in the FOPEN_NCHAR function. In Unix, the file name cannot end with the combination of a slash and a dot (/.).
  open_mode	Open mode of a specified file, including r (read text), w (write text), a (append text), rb (read byte), wb (write byte), and ab (append byte). NOTE: For the write operation, the system checks the file type. If the ELF file is written, an error is reported and the system exits.
  max_line_size	Maximum number of characters in each line, including newline characters. The minimum value is 1 and the maximum is 32767. If this parameter is not specified, the default value 1024 is used.

• DBE_FILE.WRITE_NCHAR

  Writes data in the buffer to a file. The file must be opened in national character set or write mode. This operation does not write a line terminator, and the return value is always TRUE. The text string is written in the UTF8 character set format.

  The prototype of the DBE_FILE.WRITE_NCHAR function is as follows:

  1 2 3 4

  DBE_FILE.WRITE_NCHAR( file IN DBE_FILE.FILE_TYPE, buffer IN NVARCHAR2) RETURN VOID;

  Table 23 DBE_FILE.WRITE parameters

  Parameter	Description
  file	Object of the DBE_FILE.FILE_TYPE type opened using FOPEN_NCHAR. The file must be opened in write mode. This operation does not write line terminators.
  buffer	Text data to be written to the file. The accumulated write length of each line cannot be greater than or equal to the value of max_line_size specified by FOPEN_NCHAR. Otherwise, an error is reported when the file is refreshed. NOTE: For the write operation, the system checks the file type. If the ELF file is written, an error is reported and the system exits.

• DBE_FILE.WRITE_LINE_NCHAR

  Writes data in the buffer to a file. The file must be opened in national character set or write mode. This operation automatically appends line terminators, and the return value is always TRUE. The text string is written in the UTF8 character set format.

  The prototype of the DBE_FILE.WRITE_LINE_NCHAR function is as follows:

  1 2 3 4

  DBE_FILE.WRITE_LINE_NCHAR( file IN DBE_FILE.FILE_TYPE, buffer IN NVARCHAR2) RETURN VOID;

  Table 24 DBE_FILE.WRITE_LINE parameters

  Parameter	Description
  file	Object of the DBE_FILE.FILE_TYPE type opened using FOPEN_NCHAR.
  buffer	Text data to be written to the file. The length of each line (including the newline character) cannot be greater than the value of max_line_size specified by FOPEN_NCHAR or the default value. Otherwise, an error is reported when the file is refreshed. NOTE: For the write operation, the system checks the file type. If the ELF file is written, an error is reported and the system exits.

• DBE_FILE.FORMAT_WRITE_NCHAR

  Writes formatted data to an open file. It is a DBE_FILE.WRITE_NCHAR API that allows formatting. The return value is always TRUE.

  The prototype of the DBE_FILE.FORMAT_WRITE_NCHAR function is as follows:

  1 2 3 4 5 6 7

  DBE_FILE.FORMAT_WRITE_NCHAR( file IN DBE_FILE.FILE_TYPE, format IN NVARCHAR2, arg1 IN NVARCHAR2 DEFAULT NULL, . . . arg5 IN NVARCHAR2 DEFAULT NULL) RETURN VOID;

  Table 25 DBE_FILE.FORMAT_WRITE_NCHAR parameters

  Parameter	Description
  file	Object of the DBE_FILE.FILE_TYPE type opened using FOPEN_NCHAR.
  format	Formatted string, containing the text and format characters \n and %s.
  [arg1. . .arg5]	Five optional parameters. The parameters and the positions of characters to be formatted are in one-to-one correspondence. If the parameter corresponding to a character to be formatted is not provided, an empty string is used to replace %s.

• DBE_FILE.READ_LINE_NCHAR

  Reads data from an open file and stores the read result to the buffer. It reads data to the end of each line excluding the line terminator, to the end of the file, or to the size specified by the len parameter. The length of the data to be read cannot exceed the value of max_line_size specified by FOPEN_NCHAR.

  The prototype of the DBE_FILE.READ_LINE_NCHAR stored procedure is as follows:

  1 2 3 4

  DBE_FILE.READ_LINE_NCHAR( file IN DBE_FILE.FILE_TYPE, buffer OUT NVARCHAR2, len IN INTEGER DEFAULT NULL);

  Table 26 DBE_FILE.READ_LINE parameters

  Parameter	Description
  file	Object of the DBE_FILE.FILE_TYPE type opened using FOPEN_NCHAR. The file must be opened in read mode. Otherwise, the INVALID_OPERATION exception is thrown.
  buffer	Buffer for receiving data.
  len	Number of bytes read from the file. The default value is NULL. If the default value NULL is used, max_line_size is used to specify the line size.

Examples

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-- Add the /temp/ directory to the PG_DIRECTORY system catalog as a system administrator.
CREATE OR REPLACE DIRECTORY dir AS '/tmp/';
-- Open a file and write data into the file.

DECLARE
f DBE_FILE.FILE_TYPE;
buffer VARCHAR2;
BEGIN
-- Write a file.
f := DBE_FILE.FOPEN('dir', 'sample.txt', 'w');
DBE_FILE.WRITE(f, 'A');
DBE_FILE.WRITE(f, 'B');
DBE_FILE.WRITE(f, 'C');
DBE_FILE.NEW_LINE(f);
DBE_FILE.WRITE_LINE(f, 'ABC');
DBE_FILE.FORMAT_WRITE(f, '[1 -> %s, 2 -> %s]\n', 'GaussDB', 'DBE_FILE');
DBE_FILE.CLOSE(f);
-- Read a file.
f := DBE_FILE.FOPEN('dir', 'sample.txt', 'r');
DBE_FILE.READ_LINE(f, buffer); -- ABC
DBE_FILE.READ_LINE(f, buffer); -- ABC
DBE_FILE.READ_LINE(f, buffer); -- [1 -> GaussDB, 2 -> DBE_FILE]
DBE_OUTPUT.PRINT_LINE(buffer); 
DBE_FILE.CLOSE(f);
END;
/

-- Offset the position of the file handle and obtain the current position of the file.
DECLARE
f DBE_FILE.FILE_TYPE;
buffer VARCHAR2;
pos BIGINT;
BEGIN
-- Read a file.
f := DBE_FILE.FOPEN('dir', 'sample.txt', 'r');
DBE_FILE.SEEK(f, 8);
DBE_FILE.READ_LINE(f, buffer); -- [1 -> GaussDB, 2 -> DBE_FILE]
DBE_OUTPUT.PRINT_LINE(buffer);
pos := DBE_FILE.GET_POS(f); -- 38
DBE_OUTPUT.PRINT_LINE(pos); 
DBE_FILE.CLOSE(f);
END;
/
-- NCHAR read/write API cases
DECLARE
f DBE_FILE.FILE_TYPE;
buffer NVARCHAR2;
BEGIN
-- Write a file.
f := DBE_FILE.FOPEN_NCHAR('dir', 'sample02.txt', 'w');
DBE_FILE.WRITE_NCHAR(f, 'A');
DBE_FILE.WRITE_NCHAR(f, 'B');
DBE_FILE.WRITE_NCHAR(f, 'C');
DBE_FILE.NEW_LINE(f);
DBE_FILE.WRITE_LINE_NCHAR(f, 'ABC');
DBE_FILE.FORMAT_WRITE_NCHAR(f, '[1 -> %s, 2 -> %s]\n', 'GaussDB', 'DBE_FILE');
DBE_FILE.CLOSE(f);
-- Read a file.
f := DBE_FILE.FOPEN_NCHAR('dir', 'sample02.txt', 'r');
DBE_FILE.READ_LINE_NCHAR(f, buffer); -- ABC
DBE_FILE.READ_LINE_NCHAR(f, buffer); -- ABC
DBE_FILE.READ_LINE_NCHAR(f, buffer); -- [1 -> GaussDB, 2 -> DBE_FILE]
DBE_OUTPUT.PRINT_LINE(buffer); 
DBE_FILE.CLOSE(f);
END;
/