This content originally appeared on DEV Community and was authored by Cong Li
In enterprise-level database application development, efficient access to and operation of the database is key to enhancing application performance. The GBase 8s database system offers the GCI (GBase Client Interface), a programming interface that allows developers to conveniently access and manipulate the database using the C language. This article provides a detailed guide on how to use GCI, including environment setup, program compilation, and how to run GCI programs, to help developers quickly master client-side development for the GBase database.
1. Introduction to IDS and GCI Installation Locations
Install IDS and CSDK (assuming they are installed together) at a location like
/home/gbase.Extract the GCI package (the location is not critical), for example,
/home/gci.Go to the
etcdirectory and modify theclient.kshfile:
cd /home/gci/etc
vim client.ksh
Make the following changes:
GCICLIENTDIR=/home/gci # Path to GCI
GBASEDBTCSDK=/home/gbase # Path to CSDK
GBASEDBTSERVER=ol_gbasedbt # Instance name
2. Environment Variables and Their Meanings for Compiling GCI Programs
1) Set the database connection username and password:
export DBUSER=gbasedbt
export DBPWD=Big4ifmx
(If DBUSER and DBPWD are not used in the code, these do not need to be configured.)
2) Set the installation path of CSDK:
export GBASEDBTDIR=/home/gbase
Additional Environment Variables (Optional)
1) Set the date format:
export DBDATE=Y4MD-
2) Set character encoding:
export DB_LOCALE=ZH_CN.UTF8
export CLIENT_LOCALE=ZH_CN.UTF8
3) Set the paths for the libraries needed for compilation:
export LD_LIBRARY_PATH=${GBASEDBTDIR}/lib:${GBASEDBTDIR}/lib/esql:${GBASEDBTDIR}/lib/cli
3. CMakeList Configuration
To add a new example in the demo directory under GCI, the CMakeList needs to be modified. For example, to add a case named test.c:
cd /home/gci/demo
vim CMakeList.txt
Add the following content to CMakeList.txt:
# Compile the source file test.c to generate the executable test
ADD_EXECUTABLE(test test.c)
# Specify the libraries that the executable test needs to link
TARGET_LINK_LIBRARIES(test ${LIB_CLN_NAME})
4. Demo Source Code Analysis
A sample GCI program code is provided, which includes logging into the database, executing SQL statements, etc., with explanations of the key code segments.
1) Interface Calls and Process Flow
2) Demo Example
#include "gci.h" // GCI interface definition file
GCIEnv *envhp = NULL;
GCISvcCtx *svchp = NULL;
GCIError *errhp = NULL;
GCIStmt *stmtp = NULL;
// Log into the database
int logdb()
{
GCItext *dbname = (GCItext *)"testdb"; // Database name, modify as needed (ensure the database exists in the instance)
GCItext *user = (GCItext *)"root"; // Username, modify as needed
GCItext *pswd = (GCItext *)"111111"; // Password, modify as needed
if (GCIEnvCreate(&envhp, GCI_THREADED | GCI_OBJECT, (dvoid *)0, 0, 0, 0, 0, (dvoid **)0) != GCI_SUCCESS)
{
printf("GCIEnvCreate: create env handle failed!\n");
}
if (GCIHandleAlloc((dvoid *)envhp, (dvoid **)&svchp, GCI_HTYPE_SVCCTX, 0, (dvoid **)0) != GCI_SUCCESS)
{
printf("GCIHandleAlloc: allocate svcctx handle failed!\n");
}
if (GCIHandleAlloc((dvoid *)envhp, (dvoid **)&errhp, GCI_HTYPE_ERROR, 0, (dvoid **)0) != GCI_SUCCESS)
{
printf("GCIHandleAlloc: allocate error handle failed!\n");
}
// Call the login interface to connect to the database
if (GCILogon(envhp, errhp, &svchp, user, strlen((char *)user), pswd, strlen((char *)pswd), dbname, strlen((char *)dbname)) != GCI_SUCCESS)
{
printf("logon database failed!\n");
}
}
// Execute SQL statements
{
GCIText sql[256] = {0};
// Allocate statement handle
if (GCIHandleAlloc((dvoid *)envhp, (dvoid **)&stmtp, GCI_HTYPE_STMT, 0, (dvoid **)0) != GCI_SUCCESS)
{
printf("GCIHandleAlloc: allocate stmt handle failed!\n");
}
// Prepare SQL statement
strcpy((char *)sql, "create table t_table(id int)");
GCIStmtPrepare(stmtp, errhp, sql, strlen((char *)sql), 0, 0);
// Execute the prepared SQL statement
GCIStmtExecute(svchp, stmtp, errhp, 1, 0, NULL, NULL, GCI_COMMIT_ON_SUCCESS);
}
5. Compiling and Running the GCI Program
1) Set the environment variables:
cd /home/gci/demo
source /home/gci/etc/client.ksh
If needed, set the username and password:
export DBUSER
export DBPWD
2) Run the script files clean.sh and build_linux_debug_shared.sh, then execute make:
./clean.sh
./build_linux_debug_shared.sh
make
3) Source the profile or ksh file from the IDS installation directory (e.g., /home/gbase):
source ol_gbasedbt.ksh
4) Run the executable, e.g., ./test:
Through this detailed guide, you should now have a comprehensive understanding of how to use GCI for database programming in the GBase 8s database. GCI provides an efficient and flexible way to access the database, helping developers enhance the development efficiency and performance of database applications. We hope this article will serve as a valuable resource in your GBase 8s database development.
This content originally appeared on DEV Community and was authored by Cong Li
Cong Li | Sciencx (2024-08-20T13:58:59+00:00) GBase 8s GCI Usage Guide. Retrieved from https://www.scien.cx/2024/08/20/gbase-8s-gci-usage-guide/
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