Delphi与各数据库数据类型比较

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Delphi数据类型与各数据库数据类型对比如下表，如有具体说明见表中脚注：

Delphi Type	Oracle Types	SQL Server Types	MySQL Types [1]	InterBase Types	PostgreSQL Types	SQLite Types
ftSmallint	NUMBER(p, 0)[2] (p < 5)	SMALLINT	TINYINT(M) (M > 1) SMALLINT	SMALLINT	SMALLINT	TINYINT SMALLINT
ftWord	-	TINYINT	TINYINT(M) UNSIGNED (M > 1) SMALLINT UNSIGNED YEAR	-	-	-
ftInteger	NUMBER(p, 0)[2] (4 < p < 10)	INT	MEDIUMINT MEDIUMINT UNSIGNED INT	INTEGER	INTEGER	INTEGER INT
ftLargeint	NUMBER(p, 0)[2] (9 < p < 19)	BIGINT	BIT INT UNSIGNED BIGINT BIGINT UNSIGNED	BIGINT	BIGINT	BIGINT
ftFloat	NUMBER(p, s)[2] BINARY FLOAT(FLOAT) BINARY DOUBLE	DECIMAL(p, s)[3] FLOAT REAL	DECIMAL(p, s)[3] FLOAT DOUBLE	NUMBER(p, s)[3] FLOAT DOUBLE PRECISION	DECIMAL[3] REAL DOUBLE PRECISION	DECIMAL(p, s)[3] FLOAT DOUBLE PRECISION
ftBCD	NUMBER(p, s)[2] (p < 15) and (s < 5)	DECIMAL(p, s)[3] (p < 15) and (s < 5)	DECIMAL(p, s)[3] (p < 15) and (s < 5)	DECIMAL(p, s)[3] (p < 15) and (s < 5)	DECIMAL[3]	DECIMAL[3]
ftFMTBcd	NUMBER(p, s)[2] (14 < p < 39) and> (4 < s < 39)	DECIMAL(p, s) (14 < p < 39) and (4 < s < 39)	DECIMAL(p, s)[3] (14 < p < 39) and (4 < s < 39)	DECIMAL(p, s)[3] (14 < p < 19) and (4 < s < 19)	DECIMAL[3]	DECIMAL[3]
ftCurrency	-	MONEY SMALLMONEY	-	-	MONEY	MONEY

ftBoolean	-	BIT	TINYINT[4] BOOL[4] BOOLEAN[4]	BOOLEAN	BOOLEAN	BOOLEAN

ftString	VARCHAR2 NVARCHAR2 VARCHAR CHAR NCHAR RAW[5] INTERVAL DAY TO SECOND INTERVAL DAY TO MONTH ROWID UROWID	CHAR VARCHAR	CHAR VARCHAR ENUM SET BINARY[6] VARBINARY[6]	CHAR VARCHAR	CHAR VARCHAR	CHAR VARCHAR
ftWideString	See note [7]	NCHAR NVARCHAR	See note [7]	See note [7]	See note [7]	See note [7]
ftMemo	LONG Also see note [8]	TEXT NTEXT[9]	TINYTEXT TEXT MEDIUMTEXT LONGTEXT	BLOB TEXT	TEXT	TEXT CLOB
ftWideMemo	See note[10]	NTEXT[11]	See note[10]	See note[10]	See note[10]	See note[10]
ftOraClob	CLOB NCLOB	-	-	-	-	-

ftBlob	LONG RAW	IMAGE	TINYBLOB BLOB MEDIUMBLOB LONGBLOB Spatial Data Types	BLOB BINARY	BYTEA	BLOB
ftOraBlob	BLOB	-	-	-	LARGE OBJECT	-
ftBytes	-	BINARY TIMESTAMP	BINARY	-	-	-
ftVarBytes	RAW	VARBINARY	VARBINARY	CHAR VARCHAR (CHARSET = OCTETS)	-	BINARY VARBINARY

ftDate	-	-	DATE	DATE	DATE	DATE
ftDateTime	DATE	DATE	DATETIME	TIMESTAMP	TIMESTAMP	TIMESTAMP DATETIME
ftTime	-	-	TIME	TIME	TIME	TIME
ftTimeStamp	TIMESTAMP TIMESTAMP WITH TIMEZONE	-	-	-	-	-

ftCursor	REF CURSOR	-	-	-	REFCURSOR	-
ftGuid	-	UNIQUEIDENTIFIER	-	-	-	-
ftVariant	-	SQL_VARIANT	-	-	-	-

NOT SUPPORTED	BFILE OBJECT XML	CURSOR XML TABLE	-	-	-	-

[1] – 如果FieldsAsString 选项被设置 True，则除BLOB和TEXT数据类型外，全部做为ftString来处理

[2] – Oracle NUMBER数据类型与Delphi数据类型对应方式:

if scale equals zero, provider checks values of the specific options to choose the correct Delphi type in the following order:

1.1 field precision is less or equal Precision Smallint (default is 4) - uses ftSmallint;
1.2 field precision is less or equal Precision Integer (default is 9) - uses ftInteger;
1.3 field precision is less or equal Precision LargeInt (default is 18) - uses ftLargeint;

if scale is greater than zero, the appropriate Delphi type is chosen using the following sequence of rules:.

2.1 field precision is less or equal PrecisionFloat (default is 0) - uses ftFloat;
2.2 EnableBCD is True and field precision, scale is less or equal PrecisionBCD (default is 14,4) - uses ftBCD;
2.3 EnableFMTBCD is True and field precision, scale is less or equal PrecisionFMTBCD (default is 38,38) - uses ftFMTBCD;
2.4 uses ftFloat.

[3] - The appropriate Delphi type is chosen using the following sequence of rules:

EnableBCD is True and field precision, scale is less or equal 14,4 - uses ftBCD;

EnableFMTBCD is True - uses ftFMTBCD;

uses ftFloat.

[4] - If the EnableBoolean option is True

[5] - If the RawAsString option is True

[6] - If the BinaryAsString is True

[7] - If the UseUnicode option is True, all server types mapped to ftString will be mapped to ftWideString.

[8] - If the LongStrings option is False, and the field length is greater than 255, all server types mapped to ftString will be mapped to ftMemo.

[9] - For all Delphi versions prior to BDS 2006.

[10] - If the UseUnicode option is True, in BDS 2006 and later versions all server types mapped to ftMemo will be mapped to ftWideMemo.

[11] - For BDS 2006 and higher IDE versions.