Valid For

Extract and Replicat

Description

Use the GET_COL_METADATA_FROM_INDEX function to retrieve column metadata by specifying the index of the desired column.

Database object names are returned exactly as they are defined in the hosting database, including the letter case.

Syntax

#include "usrdecs.h"
short result_code;
col_metadata_def column_meta_rec;
ERCALLBACK (GET_COL_METADATA_FROM_INDEX, &column_meta_rec, &result_code);

Buffer

typedef struct
{
  short column_index;
  char *column_name;
  long max_name_length;
  short native_data_type;
  short gg_data_type;
  short gg_sub_data_type;
  short is_nullable;
  short is_part_of_key;
  short key_column_index;
  short length;
  short precision;
  short scale;
  short source_or_target;
} col_metadata_def;

Input

column_index

The column index of the column value to be returned.

max_name_length

The maximum length of the returned column name. Typically, the maximum length is the length of the name buffer. Since the returned name is null-terminated, the maximum length should equal the maximum length of the column name.

source_or_target

One of the following to indicate whether the source or target record is being compressed.

EXIT_FN_SOURCE_VAL
EXIT_FN_TARGET_VAL

Output

column_name

The column name of the column value to be returned.

actual_name_length

The actual length of the returned name.

value_truncated

A flag (0 or 1) to indicate whether or not the value was truncated. Truncation occurs if the length of the column name plus the null terminator exceeds the maximum buffer length.

native_data_type

The native (to the database) data type of the column. Either native_data_type or dd_data_type is returned, depending on the process, as follows:

• If Extract is making the callback request for a source column, native_data_type is returned. If Extract is requesting a mapped target column, gg_data_type is returned (assuming there is a target definitions file on the system).

• If an Extract data pump is making the callback request for a source column and there is a local database, native_data_type is returned. If there is no database, gg_data_type is returned (assuming there is a source definitions file on the system). If the pump is requesting the target column, gg_data_type is returned (assuming a target definitions file exists on the system).

• If Replicat is making the callback request for the source column, then gg_data_type is returned (assuming a source definitions file exists on the system). If Replicat is requesting the source column and ASSUMETARGETDEFS is being used in the parameter file, then native_data_type is returned. If Replicat is requesting the target column, native_data_type is returned.

gg_data_type

The Oracle GoldenGate data type of the column.

gg_sub_data_type

The Oracle GoldenGate sub-type of the column.

is_nullable

Flag indicating whether the column permits a null value (TRUE or FALSE).

is_part_of_key

Flag (TRUE or FALSE) indicating whether the column is part of the key that is being used by Oracle GoldenGate.

key_column_index

Indicates the order of the columns in the index. For example, the following table has two key columns that exist in a different order from the order in which they are declared in the primary key.

CREATE TABLE ABC
(
cust_code        VARCHAR2(4),
name             VARCHAR2(30),
city             VARCHAR2(20),
state            CHAR(2),
PRIMARY KEY (city, cust_code)
USING INDEX
);

Executing the callback function for each column in the logical column order returns the following:

• cust_code returns 1

• name returns -1

• city returns 0

• state returns -1

If the column is part of the key, the value returned is the order of the column within the key.

If the column is not part of the key, a value of -1 is returned.

length

Returns the length of the column.

precision

If a numeric data type, returns the precision of the column.

scale

If a numeric data type, returns the scale.

Return Values

EXIT_FN_RET_INVALID_PARAM
EXIT_FN_RET_INVALID_CONTEXT
EXIT_FN_RET_EXCEEDED_MAX_LENGTH
EXIT_FN_RET_INVALID_COLUMN
EXIT_FN_RET_OK