The preferred storage class for a column is called its affinity. Type affinity is the recommended type for data stored in that column. If the declared type for a column contains any of the strings "REAL", "FLOA", or "DOUB" then the column has REAL affinity. SQLite Affinity Type: In order to maximize compatibility between SQLite and other database engines, SQLite supports the concept of type affinity on columns. If the declared type for a column contains the string "BLOB" or if no type is specified then the column has affinity NONE. Notice that the type VARCHAR contains the string "CHAR" and is thus assigned TEXT affinity. If the declared type of the column contains any of the strings "CHAR", "CLOB", or "TEXT" then that column has TEXT affinity. If the declared type contains the string "INT" then it is assigned INTEGER affinity. ![]() The affinity of a column is determined by the declared type of the column, according to the following rules in the order shown: The preferred storage class for a column is called its "affinity".Įach column in an SQLite 3 database is assigned one of the following type affinities: It is just that some columns, given the choice, will prefer to use one storage class over another. 2.1 Determination Of Column Affinity If the declared type contains the string INT then it is assigned INTEGER affinity. Each column in an SQLite 3 database is assigned one of the following type affinities: TEXT. Any column can still store any type of data. The preferred storage class for a column is called its 'affinity'. i assume using CubeSQL as the database server, the VARCHAR thingy still apply. i guess i use the varchar with a number to let me know that the field is a small field with max number is 10 or 255 or 4000. The important idea here is that the type is recommended, not required. quote342342: Dave SPlease read about SQLite Affinity. ![]() The type affinity of a column is the recommended type for data stored in that column. UPDATE tickets SET issend 1 This would work if SQLite can do the conversion from integer to string for you. In order to maximize compatibility between SQLite and other database engines, SQLite supports the concept of "type affinity" on columns. The value is a blob of data, stored exactly as it was input. The value is a text string, stored using the database encoding (UTF-8, UTF-16BE or UTF-16LE).īLOB. In SQLite, the datatype of a value is associated. SQLite uses a more general dynamic type system. With static typing, the datatype of a value is determined by its container - the particular column in which the value is stored. The value is a floating point value, stored as an 8-byte IEEE floating point number. Most SQL database engines (every SQL database engine other than SQLite, as far as we know) uses static, rigid typing. The value is a signed integer, stored in 1, 2, 3, 4, 6, or 8 bytes depending on the magnitude of the value. ![]() However, the dynamic typing in SQLite allows it to do things which are not possible in traditional rigidly typed databases.Įach value stored in an SQLite database (or manipulated by the database engine) has one of the following storage classes: ![]() The dynamic type system of SQLite is backwards compatible with the more common static type systems of other database engines in the sense that SQL statement that work on statically typed databases should work the same way in SQLite. In SQLite, the datatype of a value is associated with the value itself, not with its container. In this case, the SQLite engine is compiled with SQLITE_ENABLE_COLUMN_METADATA defined (by default, this is True for Windows, and False for other platforms).SQLite uses a general dynamic type system. If the type declaration contains parenthesis (to specify precision, for example VARCHAR(14)), SQLITE_TEXT is mapped to WideStringType.īlobType with a subtype of WideMemoSubTypeįireDAC uses the SQLite columns affinity: For dbExpress, the SQLite column affinities are mapped as follows:īlobType with a subtype of WideMemoSubType.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |