ColumnStore Data Types
You are viewing an old version of this article. View
the current version here.
ColumnStore supports the following data types:
| Datatypes | Column Size | Description |
|---|---|---|
| BIGINT | 8-bytes | A large integer. Numeric value with scale 0. Signed: -9,223,372,036,854,775,806 to+9,223,372,036,854,775,807 Unsigned: 0 to +18,446,744,073,709,551,613 |
| CHAR | 1, 2, 4, or 8 bytes | Holds letters and special characters of fixed length. Max length is 255. Default and minimum size is 1 byte. |
| DATE | 4-bytes | Date has year, month, and day. The internal representation of a date is a string of 4 bytes. The first 2 bytes represent the year, .5 bytes the month, and .75 bytes the day in the following format: YYYY-MM-DD. Supported range is 1000-01-01 to 9999-12-31. |
| DATETIME | 8-bytes | A date and time combination. Supported range is 1000-01-01 00:00:00 to 9999-12-31 23:59:59. |
| DECIMAL/NUMERIC | 2, 4, or 8 bytes | A packed fixed-point number that can have a specific total number of digits and with a set number of digits after a decimal. The maximum precision (total number of digits) that can be specified is 18. |
| DOUBLE/REAL | 8 bytes | Stored in 64-bit IEEE-754 floating point format. As such, the number of significant digits is about 15 and the range of values is approximately +/-1e308. The MySQL extension to specify precision and scale is not supported. “REAL” is a synonym for “DOUBLE”. |
| FLOAT | 4 bytes | Stored in 32-bit IEEE-754 floating point format. As such, the number of significant digits is about 6and the range of values is approximately +/- 1e38.The MySQL extension to specify precision and scale is not supported. |
| INTEGER/INT | 4-bytes | A normal-size integer. Numeric value with scale 0. Signed: -2,147,483,646 to 2,147,483,647. Unsigned: 0 to 4,294,967,293 |
| SMALLINT | 2-bytes | A small integer. Signed: -32,766 to 32,767. Unsigned: 0 to 65,533. |
| TINYINT | 1-byte | A very small integer. Numeric value with scale 0. Signed: -126 to +127. Unsigned: 0 to 253. |
| VARCHAR | 1, 2, 4, or 8 bytes or 8-byte token | Holds letters, numbers, and special characters of variable length. Max length = 8000 bytes or characters and minimum length = 1 byte or character. |
| TEXT | 2 GB | Holds letters, numbers, and special characters of variable length. Supported from version 1.1.0 onwards. |
| BLOB | 2 GB | Holds binary data of variable length. Supported from version 1.1.0 onwards. |
Notes
- ColumnStore treats a zero-length string as a NULL value.
- As with core MariaDB, ColumnStore employs “saturation semantics” on integer values. This means that if a value is inserted into an integer field that is too big/small for it to hold (i.e. it is more negative or more positive than the values indicated above), ColumnStore will “saturate” that value to the min/max value indicated above as appropriate. For example, for a SMALLINT column, if 32800 is attempted, the actual value inserted will be 32767.
- ColumnStore largest negative and positive numbers appears to be 2 less than what MariaDB supports. ColumnStore reserves these for its internal use and they cannot be used. For example, if there is a need to store -128 in a column, the TINYINT datatype cannot be used; the SMALLINT datatype must be used instead. If the value -128 is inserted into a TINYINT column, ColumnStore will saturate it to -126 (and issue a warning).
- ColumnStore truncates rather than rounds decimal constants that have too many digits after the decimal point during bulk load and when running SELECT statements. For INSERT and UPDATE, however, the MariaDB parser will round such constants. You should verify that ETL tools used and any INSERT/UPDATEstatements only specify the correct number of decimal digits to avoid potential confusion.
- An optional display width may be added to the BIGINT, INTEGER/INT, SMALLINT & TINYINT columns. As with core MariaDB tables, this value does not affect the internal storage requirements of the column nor does it affect the valid value ranges.
- All columns in ColumnStore are nullable and the default value for any column is NULL. You may optionally specify NOT NULL for any column and/or one with a DEFAULT value.
Comments
Comments loading...
Content reproduced on this site is the property of its respective owners,
and this content is not reviewed in advance by MariaDB. The views, information and opinions
expressed by this content do not necessarily represent those of MariaDB or any other party.
