In order to access relational databases, Zim client-server generates SQL statements. You can see the statements generated by setting SQLTRACE on. Statements are generated when Zim statements containing references to SQL tables are parsed, compiled, or executed interpretively. Previewing the SQL statements generated provides an insight into the type or amount of work the database…
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Zim is capable of executing database commands in either of these three modes: SQLMODE SQL mode SERVERMODE Zim Integrated Server mode ZIMMODE Standard Zim mode The default mode of operation is SERVERMODE. For all database servers except Zim Integrated Server, SERVERMODE and SQLMODE behave identically. In SERVERMODE, a Zim client accessing tables on Zim Integrated…
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A dynamic configuration setting called “block factor” can be used to tune performance. This factor is the number of records retrieved by Zim each time it fetches records from the database. The larger the number, the fewer times Zim has to query the database, and the more time it takes to retrieve a block. So,…
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The “SET SQLCOMPILE” Command Zim is designed to take advantage of many characteristics of a given SQL server. Many SQL servers provide compile time facilities to increase performance at runtime. A compile time option enables you to control when the database server does certain compilation functions such as statement parsing. If SQLCOMPILE is OFF, then…
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All SQL servers require that some type of connection be established between a client program and the server before any database operations can be attempted. In Zim, a connection between a Zim application and an SQL server is established by the “CONNECT” command and removed by the “DISCONNECT” command. During the execution of any Zim…
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If you are developing a Zim application to run against an existing SQL database, you must create an equivalent representation of that data in Zim. Zim’s definition interface translates SQL definitions into equivalent definitions in Zim. The mapping of SQL tables to Zim EntitySets or data relationships is straight-forward. A Zim developer must first establish…
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If you have developed an application in Zim and want to maintain a portion of the data in an SQL database, the definitions of those objects must be maintained in the SQL database as well as in Zim. Zim’s SQL definition interface translates Zim definitions into equivalent definitions in the SQL server environment. Refer to…
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If the Zim application being developed is based on an existing SQL database, then the Zim definition interface needs to be executed in order to import the definitions of the relevant tables from the SQL server and populate the Zim data dictionary so that the application can be developed. Conversely, if the Zim application has…
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Zim supports two types of transactions: implicit and explicit. An implicit transaction is associated with each individual Zim command that accesses the database in some manner (either read/only or read/write). When the command ends, all locks that were acquired are released and any database updates are committed to the database. If the command fails (e.g.…
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In Client-Server applications, you do not have to do anything special to access or manipulate data stored in the SQL database. The data definitions of objects under Zim’s control and the data definitions of objects not under Zim’s control are exactly the same. To an application, Zim manipulates both in exactly the same way. The…
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