Table¶

CrosDB Table is a collection of rows(record or tuple) and columns.

• Table schema is mapped from C Struct, so this is a kind of C Struct ORM(Object Relational Mapping).
• The C struct is expanded into each single fields for composite data type like array, nested struct etc.
• Each table can have only one Primary key.
• Each table can hve many secondray indexes.

Primary Key(PK)¶

• Each table can have only one Primray Key, which is used to identify the row uniquely.
• Primay Key column list shouldn't change during the row lifecycle.
• Primary Key is implemented with unique HASH index for high performance. You can change to RBTREE as well.

Guide¶

• If table exists and pFields is different with table schema, table will be upgraded automatically.
• If you want to know if table exists, you can use CROSS_OPEN to get handle first.
• Primary Key is HASH type by default to achieve highest performance.
• If you don't care about performance, you can set CROSS_RBTREE to create RBTREE type Primary Key.
• If you need both exact match and range match for Primary Key, you can create another RBTREE index with same column list.

Example¶

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// Create table with PrimaryKey="prefix,mask", HASH Type
ret = cross_dbTblCreate (hDb, &hRtTbl, "route", route_schema, "prefix,mask", 0);
CHECK (ret, "Failed to create route table");

// Create table with PrimaryKey="prefix,mask", RBTREE Type
ret = cross_dbTblCreate (hDb, &hRtTbl, "route", route_schema, "prefix,mask", CROSS_RBTREE);
CHECK (ret, "Failed to create route table");

// Get table handle
ret = cross_dbTblCreate (hDb, &hRtTbl, "route", NULL, NULL, CROSS_OPEN);
CHECK (ret, "Failed to get route table");

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