External table option processing

This section contains more information about how the system processes the external table options.

General input row processing
The system uses a line-oriented input format whereby one line of text is an input row. It operates by isolating successive rows in the input stream. For each new row, the system increments a row counter (starting at 1) and analyzes the contents of the row.
Input fields and table columns
The system determines the shape of input rows by inspecting the schema of the target table. The fields are paired left to right with the columns in the target schema. When the system locates the start of a field, the declared type of the corresponding target column guides further processing.
Absence of a value in a record
In SQL, a record must include a value if a column is declared as not null. When a record contains no value for a column, the column is considered to be null. The system provides explicit and implicit methods for conveying nullness.
Legal characters for external tables
Input is composed of the printing characters (bytes 33 - 255), space character (byte 32), horizontal tab character (byte 9), line feed character (byte 10), and carriage return character (byte 13). By default, you cannot use the nonprinting control characters.

Parent topic: External table options