Choose data types for host variables
When you access a database column in your program, you must declare a host variable of the appropriate C or data type to hold the data. Corresponding SQL and host variable data types lists the SQL data types of the HCL OneDB™ and the corresponding data types that you can declare for host-variables. Corresponding SQL and host variable data types specific to HCL OneDB lists the additional SQL data types available with HCL OneDB and the data types that you can use as host variables for those types of columns. Both figures include a reference to the section or chapter in this book where you can obtain more information about the host-variable data type. For more information about the SQL data types that you can assign to database columns, see the HCL OneDB Guide to SQL: Reference.
| SQL data type | ESQL/C predefined data type | C language type | See |
|---|---|---|---|
| BIGINT | BIGINT | 8-byte integer | Numeric data types |
| BIGSERIAL | BIGINT | 8-byte integer | Numeric data types |
| BOOLEAN | boolean | SQL data types and ESQL/C header files that are specific to HCL OneDB | |
| BYTE | ifx_loc_t or loc_t | Simple large objects | |
| CHAR(n) CHARACTER(n) |
fixchar [n] or string [n+1] | char [n + 1] or char * | Character and string data types |
| DATE | date | 4-byte integer | Time data types |
| DATETIME | datetime or dtime_t | Time data types | |
| DECIMAL DEC NUMERIC MONEY |
decimal or dec_t | Numeric data types | |
| FLOAT DOUBLE PRECISION |
double | Time data types | |
| INT8 | int8 or ifx_int8_t | Numeric data types | |
| INTEGER INT |
4-byte integer | Numeric data types | |
| INTERVAL | interval or intrvl_t | Time data types | |
| LVARCHAR | lvarchar | char [n + 1] or char * | Character and string data types |
| NCHAR(n) | fixchar [n] or string [n+1] | char [n + 1] or char * | Character and string data types |
| NVARCHAR(m) | varchar[m+1] or string [m+1] | char [m+1] | Character and string data types |
| SERIAL | 4-byte integer | Numeric data types | |
| SERIAL8 | int8 or ifx_int8_t | Numeric data types | |
| SMALLFLOAT REAL |
float | Numeric data types | |
| SMALLINT | 2-byte integer | Numeric data types | |
| TEXT | loc_t | Simple large objects | |
| VARCHAR(m,x) | varchar[m+1] or string [m+1] | char d[m+1] | Character and string data types |
| SQL data type | ESQL/C predefined data type | See |
|---|---|---|
| BLOB | ifx_lo_t | Smart large objects |
| CLOB | ifx_lo_t | Smart large objects |
| LIST(e) | collection | Smart large objects |
| MULTISET(e) | collection | Complex data types |
| Opaque data type | lvarchar, fixed binary, or var binary | Opaque data types |
| ROW(...) | row | Complex data types |
| SET(e) | collection | Complex data types |