Geodatabase field data typesRelease 9.3When you create feature classes and tables, you select a data type for each field. The available types include a variety ofnumber types, text, date, binary large objects (BLOBs), or globally unique identifiers (GUIDs). Choosing the correct data typeallows you to correctly store the data and will facilitate your analysis, data management, and business needs.The data types explained in this topic include all the data types available when creating a feature class or table with ArcMap orArcCatalog. If you store your data in an ArcSDE geodatabase or a personal geodatabase, the data types between ArcGIS andyour database management system (DBMS) might not match directly. The types are matched to the closest data type availablein the DBMS. This process is referred to as data type mapping. In this process, it is possible that the values will be stored inthe DBMS as a different type, applying different criteria to the data attribute. To learn more about the data type mappingprocess with your database management system, see Data types in the DBMS.NumbersYou can store numbers in one of four numeric data types:Short integersLong integersSingle-precision floating point numbers, often referred to as floatsDouble-precision floating point numbers, commonly called doublesIn choosing the data type, first consider the need for whole numbers versus fractional numbers. If you just need to store wholenumbers, such as 12 or 12,345,678, specify a short or long integer. If you need to store fractional numbers that have decimalplaces, such as 0.23 or 1234.5678, specify a float or a double.Secondly, when choosing between a short or long integer, or between a float or double, choose the data type that takes up theleast storage space required. This will not only minimize the amount of storage required but will also improve performance. Ifyou need to store integers between -32,768 and 32,767 only, specify the short integer data type, because it takes up only 2bytes, whereas the long integer data type takes up 4. If you need to store fractional numbers between -3.4E-38 and 1.2E38only, specify the float data type, because it takes up 4 bytes, whereas the double data type takes up 8. The following table listsdata types, their ranges, and storage requirements. The ranges listed are for file and personal geodatabases. Ranges differslightly in ArcSDE geodatabases.Data type Storable range Size(bytes)ApplicationsShort integer -32,768 to 32,767 2 Numeric values without fractional valueswithin specific range; coded valuesLong integer -2,147,483,648 to2,147,483,6474 Numeric values without fractional valueswithin specific rangeSingle-precisionfloating-point number (float)Approximately -3.4E38to 1.2E384 Numeric values with fractional valueswithin specific rangeDouble-precisionfloating-point number(double)Approximately -2.2E308to 1.8E3088 Numeric values with fractional valueswithin specific rangeIf you're specifying numeric fields for a table in a file or personal geodatabase, you need only specify the data type. If you'respecifying numeric fields for an ArcSDE geodatabase, you additionally specify the precision, which is the maximum length ofthe field, and scale, which is the maximum number of decimal places.Specifying the precision and scale allows you to restrict the range of values and number formats a field can accept, giving yougreater control. For example, if you specify a float with a precision of 4 and a scale of 2, the field will accept 12.34. If you try toenter 12.345 into the field, an error message would display, as this exceeds the maximum number of digits and decimal placesallowed. On the other hand, if you specify a float with a precision of 5 and a scale of 3, the field would let you enter the 12.345.Data types and their possible precision and scale values are listed in the following table. Use this table to help you choose datatype, precision, and scale for ArcSDE geodatabases.Data type Precision (field length) Scale (decimal places)Geodatabase field data types http://webhelp.esri.com/arcgisserver/9.3/java/geodatabases/geodata-953...1 of 5 2/6/2011 8:16 AMShort integer* 1–4 (Oracle)1–5 (SQL Server, PostgreSQL)5 (DB2, Informix)0Long integer 5–10 (Oracle)6-10 (PostgreSQL)6-9 (DB2, Informix, and SQL Server)0Float 1–6 1–6Double 7+ 0+*The precision for short integers differs depending on the DBMS. Short integers with a precision of 4 in Oracle can store valuesup to 9,999. Short integers with a precision of 5 in SQL Server, DB2, and Informix can store values up to 32,767. There is noreason for you to specify a precision for short integers in ArcCatalog on any database except Oracle. There is no reason tospecify a precision for long integers in ArcCatalog on SQL Server or PostgreSQL databases.The following provides examples of number ranges and how you could store them in an ArcSDE geodatabase:Range Data type Precision (field length) Scale (decimal places)0 to 99 Short integer 2 0-99 to 99* Short integer 3 00 to 99,999 Long integer 5 0-99,999 to 99,999* Long integer 6 00.001 to 0.999 Float 4 31,000.00 to 9,999.99 Float 6 2-123,456.78 to 0* Double 9 20 to 1,234.56789 Double 9 5*Negative numbers require additional precision to store the negative sign.Computers can only store a limited number of digits, depending on the storage space being allocated. Fields of data typedouble in file, personal, and ArcSDE geodatabases can precisely store numbers that contain up to 15 digits only, because thisis the longest number that can fit into 8 bytes of storage space. Numbers that have more digits than this are rounded andstored in a format similar to scientific notation, making them approximate numbers only. For example, if you enter the 20-digitnumber 12,345,678,901,234,567,890, it is rounded and stored as the 15-digit number 1.23456789012346E+19. The codedvalue at the end, E+19, defines the placement of the decimal point.Floats in file and personal geodatabases can store precisely numbers that contain up to 6 digits only. For example, you couldnot store the number 123,456.7 precisely in a float field because this number contains more than six digits. You can enter thenumber into a float field in a file or personal geodatabase, but it will be rounded to 123,457, a number containing thepermissible 6 digits. If you need to store this number precisely, you could store it in a double field. Float fields in ArcSDEgeodatabases do not let you enter more digits than the precision for