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The basic requirement for FairCom DB ISAM and low-level data and index files to work with c-treeDB is that the data file must have a DODA describing the fields and an IFIL describing the data and index structures. The DODA resource must have an entry for every field that forms a data record.
The c-treeDB interface was designed to work best with ISEG structures with schema segments, that is, each index segment is a field declared in a DODA entry. c-treeDB works with index segments defined in the ISEG structures using absolute record offsets and arbitrary lengths, that may or may not span more than one field in the record buffer, however, advanced features of c-treeDB may not work as expected.
ctdbAlterTable(), ctdbSetRecordOn(), and ctdbFindRecord() are typical examples of functions that may not work as expected when dealing with absolute segment offsets.
Another source of problems may come from non-standard usage of c-tree field types declared in the DODA. There have been cases where CT_ARRAY fields being used as variable-length data, CT_STRING fields being used as fixed string fields. Another source of concern are CT_DATE, CT_TIME, and CT_DATETIME fields whose contents will not be compatible with the definitions of date and time used by c-treeDB.
c-treeDB was designed from the outset to be as compatible as possible with existing c-tree ISAM and low-level data. However, there are situations where c-treeDB may not be able to handle very specific data type arrangements used by FairCom DB users in their custom applications.
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Tables created with c-treeDB are 100% compatible with FairCom DB SQL, even when tables are created without RECBYT or ROWID indexes. Tables created with c-treeDB but without transaction processing flags will not be able to participate in SQL transactions or transaction isolation levels.
Tables created by FairCom DB applications must be 100% compatible with c-treeDB to get the full benefit of all FairCom DB SQL commands and features. FairCom DB SQL makes extensive use of ctdbAlterTable(), ctdbFindRecord() and ctdbRecordSetOn(); any FairCom DB tables that do not support these operations will have reduced compatibility with FairCom DB SQL.
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FairCom DB SQL Field Type |
c-treeDB/c-treeDB .NET Field Type |
|---|---|
BIT |
CT_BOOL |
TINYINT |
CT_TINYINT |
SMALLINT |
CT_SMALLINT |
INTEGER |
CT_INTEGER |
FLOAT |
CT_FLOAT |
DOUBLE |
CT_DOUBLE |
TID |
CT_UINTEGER |
CHAR |
CT_CHARS |
VARCHAR |
CT_VARCHAR |
LVARCHAR |
CT_LVARCHAR |
BINARY |
CT_BINARY |
VARBINARY |
CT_VARBINARY |
LVARBINARY |
CT_LVARBIN |
DATE |
CT_DATE |
TIME |
CT_TIME |
TIMESTAMP |
CT_TIMESTAMP |
BIGINT |
CT_BIGINT |
MONEY |
CT_CURRENCY |
NUMBER, NUMERIC, DECIMAL |
CT_NUMBER |
