Data Conversion on Insertion

The data you enter into your Sybase IQ database will likely come from diverse sources.

Not all of your data will match the Sybase IQ data types exactly. Some of it will need to be converted. Data is converted in two ways: explicitly and implicitly. For example, to insert INT data into a CHAR column you must convert it explicitly.

Implicit conversions can occur:

When you insert data selected from another column in the same database
When you insert data selected from another database
When you load data from a flat file

When an explicit conversion is needed, the way that you specify the conversion depends on whether you are loading from a flat file or inserting selected rows:

In the LOAD TABLE statement, you convert data explicitly by specifying a format in the column-spec.
In the INSERT statement, you convert data explicitly using the data conversion functions CAST, CONVERT, and DATEPART in the SELECT statement or VALUES list.

While most Sybase IQ data types are fully compatible with SQL Anywhere and Adaptive Server Enterprise data types of the same name, there are some differences.

For compatibility among versions, a few data types have been defined as synonyms of other data types:

DECIMAL is a synonym for NUMERIC.
INTEGER is a synonym for INT.
DATETIME is a synonym for TIMESTAMP.
FLOAT (precision) is a synonym for REAL or DOUBLE, depending on the value of precision. For Adaptive Server Enterprise, REAL is used for precision less than or equal to 15, and DOUBLE for precision greater than 15. For Sybase IQ and SQL Anywhere, the cutoff is platform-dependent, but on all platforms the cutoff value is greater than 22.
MONEY is an Adaptive Server Enterprise-compatible synonym for NUMERIC(19,4), allowing NULL.
SMALLMONEY is an Adaptive Server Enterprise-compatible synonym for NUMERIC(10,4), allowing NULL.

You can use a synonym interchangeably with its standard data type. Data is stored internally as the standard data type, where synonyms exist. In error messages, the standard name appears in place of the synonym.

Note: By default, Sybase IQ assumes that input data is binary (numeric data) and tries to insert it that way. However, this presumes that the input column length in bytes must match the destination column length in bytes. If not, the insert will fail or lead to unexpected results. For example, if you attempt to insert an input column with integer data of 4 bytes into a SMALLINT destination column, Sybase IQ loads only the first 2 bytes of that input column.

Data from Pre-Version 15 Sybase IQ
If you are moving data into Sybase IQ version 15.x from an earlier version, you must convert certain data types before inserting or loading them.
Load Conversion Options
The following table lists the conversion options for the LOAD TABLE statement in alphabetical order and gives a brief description of what each option does.
Column Width Issues
Sybase IQ assumes the width of the input data is the same as the destination column width and reads the input file accordingly.
Faster Date and Time Loads
Sybase IQ has performance optimizations built in for ascii-to-binary conversions on date, time, and datetime data during loads. If the raw data you are loading exactly matches one of these formats, you can significantly decrease load time by using the appropriate format.
ASCII Input Conversion
Convert ASCII input data to binary.
The DATE Option
Use the DATE conversion option to insert ASCII data that is stored in a fixed format into a DATE column.
The DATETIME Conversion Option
Use the DATETIME conversion option to insert ASCII data that is stored in a fixed format into a TIME or TIMESTAMP or DATETIME column.
NULL Data Conversions
Use the NULL conversion option to convert specific values in the input data to NULLs when inserting into Sybase IQ column indexes.

Parent topic: Data Import and Export

Related concepts

Inserting Specified Values Row by Row

Explicit Data Conversions in IQ

Matching Adaptive Server Enterprise Data Types