Labels:text | menu | screenshot | number | font OCR: TABLE 2. Workgroup Server Features Gupta Oracle Workgroup Sybase 10.0.1 Microsoft SQL Feature Watcom SQL 4.0 SOLBase 6.0 Server Workgroup Server Server 6.0 SERVER ARCHITECTURE COMPARISON Server-based Declarative RI Declarative RI Declarative RI Declarative RI Declarative RI, isolation referential integrity level Cascading updates Yes No No No No and deletes Concurrency model Readers block writers, Readers block writers, Readers, writers do not Readers block writers, Readers block writers, writers block readers writers block readers block each other. Trans- writers block readers writers block readers actions can be made read- only and serializable ) Isolation levels Four isolation levels from Cursor stability. Oracle's multiversioning Cursor stability, Cursor stability, repeatable dirty reads to serializable repeatable read approach does not directly repeatable read read, dirty read optimizer transactions correspond with the four ANSI Isolation levels Physical access Heap, B-tree index Heap, B-tree index, Heap, B-tree index. Heap, B-tree index, Heap, B-tree index. structures clustered index clustered index, hashing. clustered index clustered index hashed cluster Optimizer Cost-based, self-tuning, Cost-based. Maintains Cost-based or rule-based. Cost-based; uses Cost-based; uses histo- simple - no histogram, somne statistics dynam- Cost-based newly added in histogram gram to capture data no statistics gathering. ically, others manually Oracle7. Updated using distribution. Read-ahead no selectivity features using UPDATE STATISTICS ANALYZE command. Can improvements make command. Has range of compute statistics for whole statistics collection faster statistics including table/index, or extrapolate selectivity. No histogram based on sample of rows. Rule-based requires hand- tuning during development Locking granularity Row level Page level Row level Page level Page level SERVER PROGRAMMING FEATURES Stored procedure New this year in version New this year in version PL/SQL Transact SQL Transact SQL language 4.0; based on ANSI 6.0; a subset of SQL- draft standard Windows SAL. Has sup- port for stored statements Stored procedure None None Supports packages for Procedure group created Procedure group created management collecting and adminis: by using ; # extension, Can by using ; # oxtension. tering related sets of drop procedure group Can drop procedure procedures together group together Static/dynamic SQL No Yes Yes No Yes in stored procedures Procedures return rows Yes, compatible with Yes, compatible with No (coming in version 7.2) Yes. compatible with Yes, compatible with ODBC ODBC ODBC ODBC Server cursors Bidirectional Bidirectional Forward Only Forward Only Bidirectional Client-simulated cursors No Yes Na Yes Yes SQL conformance SQL-89, SQL-92 Entry Level SQL-89 SQL-92 SQL-92 SQL-92 OTHER FEATURES Replication Replication from Watcom Publish/subscribe Read-only snapshots in Publish/Subscribe Publish/Subscribe desktop to Watcom server paradigm Oracle7. Update any- paradigm paradigm Plans to integrate with where replication in Sybase Replication Server. Enterprise Server. Personal Oracle7 supports read-only replication. Distributed database No Yes, supports two-phase Distributed option is not Not supported with 10.01 Requires upgrade support commit shipped with Workgroup Server and may require upgrade Replication features Manual log transfer. (Repli, Currently none (coming Requires upgrade Requires upgrade Included in version 6.0 cation product under with separate SQL Ranger development) product ODBC, server APls Both available: ODBC Both available Both available Both available Both available recommended Remote administrative SQL only GUI-based Character-mode SQL only, monitoring Various Gui tools tools SQLConsole BOL'DBA through SQLMonitor SNMP support No Yes No No No
