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CRDSS <br />TASK MEMORANDUM 1.05-7 <br />Study of System Integration Issues <br />Database - Use of Embedded SQL in CRDSS <br />1.0 ISSUE <br />Low-level queries of the CRDSS database will be made using Embedded Standard Query Language <br />(ESQL) calls. Such queries are used by programs that need to non-interactively retrieve data. A <br />library of routines will be developed to retrieve data from the database and return data objects to the <br />calling programs. This memorandum discusses the following issues related to using ESQL in the <br />CRDSS: <br />What INFORMIX products need to be installed on the workstation in order to use ESQL to <br />? <br />access the CRDSS database? How does this relate to remote access of the database? <br />For developers, what "include" files are necessary in source code, and what libraries need <br />? <br />to be linked when compiling? <br />What reference documents are used to define ESQL syntax? <br />? <br />Are there limitations to the size of data objects that can be accessed from the database? <br />? <br />What are the security issues involved with using ESQL (can anyone write code to read the <br />? <br />database)? <br />What performance issues must be addressed (are there different ways of using ESQL, some <br />? <br />of which are more efficient than others)? <br />2.0 DISCUSSION/ANALYSIS <br />What INFORMIX products need to be installed on the workstation in order to use ESQL to <br />? <br />access the CRDSS database? How does this relate to remote access of the database? <br />The State has purchased several products from INFORMIX that access an INFORMIX database. <br />The chosen core configuration for the CRDSS includes INFORMIX Embedded SQL for C (ESQL/C) <br />and INFORMIX-Online. INFORMIX-Online is the name of the INFORMIX database engine. <br />INFORMIX-ESQL/C is the name of the INFORMIX access tool that will be used to access the <br />CRDSS INFORMIX database. ESQL/C allows for the use of SQL within C programs. Compiling <br />and running these programs is the same as compiling and running any C program accept for applying <br />the ESQL pre-processor to the program code prior to compilation. If the workstation executing the <br />ESQL/C application does not have the database located locally, then two other INFORMIX products <br />are required. INFORMIX has two co nnectivity products for client/server configurations. One <br />product, INFORMIX-Star, is placed on the database server machine. When installed and running, <br />INFORMIX-Star listens for and validates incoming connections from users on a network. The other <br />product, INFORMIX-Net, is placed on the client or local workstation. When installed and running, <br />1 <br />A275 05.10.94 1.05-7 Malers, Rohlfs <br />