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Data Types for Qt-supported Database Systems

Recommended Data Types for Qt-Supported Database Systems

This table shows the recommended data types for extracting data from the databases supported in Qt. Note that types used in Qt are not necessarily valid as input types to a specific database system. e.g., A double might work perfectly as input for floating point records in a particular database, but not necessarily as a storage format for output from that database, because it would be stored with 64-bit precision in C++.

IBM DB2 Data Types

IBM DB2 data type SQL type description Recommended input (C++ or Qt data type)
SMALLINT 16-bit signed integer typedef qint16
INTEGER 32-bit signed integer typedef qint32
BIGINT 64-bit signed integer typedef qint64
REAL 32-bit Single-precision floating point By default mapping to QString
DOUBLE PRECISION 64-bit Double-precision floating point By default mapping to QString
FLOAT 64-bit Double-precision floating point By default mapping to QString
CHAR Fixed-length, null-terminated character string Mapped to QString
VARCHAR Null-terminated varying length string Mapped to QString
LONG VARCHAR Not null-terminated varying length character string Mapped to QString
BLOB Not null-terminated varying binary string with 4-byte string length indicator Mapped to QByteArray
CLOB Character large string object Mapped to QString
DATE Null-terminated character string of the following format: yyyy-mm-dd Mapped to QDate
TIME Null-terminated character string of the following format: hh.mm.ss Mapped to QTime
TIMESTAMP Null-terminated character string of the following format: yyyy-mm-dd-hh.mm.ss.nnnnnn Mapped to QDateTime

Borland InterBase Data Types

Borland InterBase data type SQL type description Recommended input (C++ or Qt data type)
BOOLEAN Boolean bool
TINYINT 8 bit signed integer typedef qint8
SMALLINT 16-bit signed integer typedef qint16
INTEGER 32-bit signed integer typedef qint32
BIGINT LONG 64-bit signed integer typedef qint64
REAL FLOAT 32-bit floating point By default mapping to QString
FLOAT 64-bit floating point By default mapping to QString
DOUBLE 64-bit floating point By default mapping to QString
DOUBLE PRECISION 64-bit Double-precision floating point By default mapping to QString
VARCHAR STRING Character string, Unicode Mapped to QString
CLOB Character large string object Mapped to QString
DATE Displays date. Format: 'yyyy-mm-dd' Mapped to QDate
TIME Displays time. Format is 'hh:mm:ss' in 24-hour format Mapped to QTime
TIMESTAMP Displays a timestamp. Format is 'yyyy-mm-dd hh:mm:ss' Mapped to QDateTime

MySQL Data Types

MySQL data type SQL type description Recommended input (C++ or Qt data type)
TINYINT 8 bit signed integer typedef qint8
TINYINT UNSIGNED 8 bit unsigned integer typedef quint8
SMALLINT 16-bit signed integer typedef qint16
SMALLINT UNSIGNED 16-bit unsigned integer typedef quint16
INT 32-bit signed integer typedef qint32
INT UNSIGNED 32-bit unsigned integer typedef quint32
BIGINT 64-bit signed integer typedef qint64
FLOAT 32-bit Floating Point By default mapping to QString
DOUBLE 64-bit Floating Point By default mapping to QString
CHAR Character string Mapped to QString
VARCHAR Character string Mapped to QString
TINYTEXT Character string Mapped to QString
TEXT Character string Mapped to QString
MEDIUMTEXT Character string Mapped to QString
LONGTEXT Character string Mapped to QString
CLOB Character large string object Mapped to QString
all BLOB types BLOB Mapped to QByteArray
DATE Date without Time Mapped to QDate
DATETIME Date and Time Mapped to QDateTime
TIMESTAMP Date and Time Mapped to QDateTime
TIME Time Mapped to QTime
YEAR Year (int) Mapped to QDateTime
ENUM Enumeration of Value Set Mapped to QString

Oracle Call Interface Data Types

Oracle Call Interface data type SQL type description Recommended input (C++ or Qt data type)
NUMBER FLOAT, DOUBLE, PRECISIONc REAL By default mapping to QString
NUMBER(38) INTEGER INT SMALLINT typedef qint8/16/32/64
NUMBER(p,s) NUMERIC(p,s) DECIMAL(p,s)a By default mapping to QString
NVARCHAR2(n) Character string (NATIONAL CHARACTER VARYING(n) NATIONAL CHAR VARYING(n) NCHAR VARYING(n)) Mapped to QString
NCHAR(n) Character string (NATIONAL CHARACTER(n) NATIONAL CHAR(n) NCHAR(n)) Mapped to QString
CHAR(n) Character string (CHARACTER(n) CHAR(n)) Mapped to QString
CLOB Character large string object Mapped to QString
BLOB A binary large object Mapped to QByteArray
TIMESTAMP Year, month, and day values of date, as well as hour, minute, and second values of time Mapped to QDateTime

ODBC Data Types

ODBC data type SQL type description Recommended input (C++ or Qt data type)
BIT Boolean BOOL
TINYINT 8 bit integer typedef qint8
SMALLINT 16-bit signed integer typedef qint16
INTEGER 32-bit signed integer typedef qint32
BIGINT 64-bit signed integer typedef qint64
REAL 32-bit Single-precision floating point By default mapping to QString
FLOAT 64-bit Double floating point By default mapping to QString
DOUBLE 64-bit Double floating point By default mapping to QString
CHAR Character string Mapped to QString
VARCHAR Character string Mapped to QString
LONGVARCHAR Character string Mapped to QString
CLOB Character large string object Mapped to QString
DATE Character string Mapped to QDate
TIME Character Time, Character string Mapped to QTime
TIMESTAMP Character Time, Character string Mapped to QDateTime

PostgreSQL Data Types

PostgreSQL data type SQL type description Recommended input (C++ or Qt data type)
BOOLEAN Boolean bool
SMALLINT 16-bit signed integer typedef qint16
INTEGER 32-bit signed integer typedef qint32
BIGINT 64-bit signed integer typedef qint64
REAL 32-bit variable-precision floating point By default mapping to QString
DOUBLE PRECISION 64-bit variable-precision floating point By default mapping to QString
DECIMAL VARIABLE user-specified precision, exact Mapped to QString
NUMERIC VARIABLE user-specified precision, exact Mapped to QString
VARCHAR variable-length character string Mapped to QString
CHARACTER Character string of fixed-length Mapped to QString
TEXT Character string of variable-length Mapped to QString
CLOB Character large string object Mapped to QString
TIMESTAMP 8 bytes, both date and time Mapped to QDateTime
TIMESTAMP 8 bytes, both date and time, with time zone Mapped to QDateTime
DATE 4 bytes, dates only Mapped to QDate
TIME 8 bytes, times of day only 00:00:00.00 - 23:59:59.99 Mapped to QTime
TIME 12 bytes times of day only, with time zone 00:00:00.00+12 Mapped to QDateTime

QSQLITE SQLite version 3 Data Types

QSQLITE SQLite version 3 data type SQL type description Recommended input (C++ or Qt data type)
NULL NULL value. NULL
INTEGER Signed integer, stored in 8, 16, 24, 32, 48, or 64-bits depending on the magnitude of the value. typedef qint8/16/32/64
REAL 64-bit floating point value. By default mapping to QString
TEXT Character string (UTF-8, UTF-16BE or UTF-16-LE). Mapped to QString
CLOB Character large string object Mapped to QString
BLOB The value is a BLOB of data, stored exactly as it was input. Mapped to QByteArray

Sybase Adaptive Server Data Types

Sybase Adaptive Server data type SQL type description Recommended input (C++ or Qt data type)
BINARY Describes a fixed-length binary value up to 255 bytes in size. Mapped to QByteArray
CHAR Character String Mapped to QString
DATETIME Date and time. Range: 1753-01-01 00:00:00 through 9999-12-31 23:59:59. Mapped to QDateTime
NCHAR Character String of fixed length Mapped to QString
NVARACHAR Character String of variable length Mapped to QString
VARCHAR Character String of fixed length Mapped to QString
CLOB Character large string object Mapped to QString
TIMESTAMP A unique number within a database Mapped to QString
SMALLDATETIME Date and time. Range: 1900-01-01 00:00 through 2079-12-31 23:59 Mapped to QDateTime
UNICHAR Character String of fixed length.(Unicode) Mapped to QString
UNIVARCHAR Character String of variable length.(Unicode) Mapped to QString
VARBINARY Describes a variable-length binary value up to 255 bytes in size Mapped to QByteArray

SQLite Version 2

SQLite version 2 is "typeless". This means that you can store any kind of data you want in any column of any table, regardless of the declared data type of that column. We recommend that you map the data to QString.

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