v2.1

About MogDB
- MogDB Introduction
- Comparison Between MogDB and openGauss
- MogDB Release Notes
  - MogDB 2.1.1
  - MogDB 2.1.0
- Open Source Components
- Usage Limitations
- Terms of Use
Quick Start
- MogDB Playground
- Container-based MogDB Installation
- Installation on a Single Node
- MogDB Access
  - Use CLI to Access MogDB
    - gsql
    - pgcli
  - Use GUI to Access MogDB
    - Data Studio
    - DBeaver
  - Use Middleware to Access MogDB
    - Use WebLogic to Configure MogDB Data Sources
    - Use WebSphere to Configure MogDB Data Sources
  - Use Programming Language to Access MogDB
    - Java
    - C/C++
    - Python
    - Go
    - Rust
    - NodeJS
- Using Sample Dataset Mogila
Characteristic Description
Installation Guide
- Container Installation
- Simplified Installation Process
- Standard Installation
  - Installation Overview
  - Preparing for Installation
    - Environment Requirement
    - Modifying OS Configuration
  - Installing MogDB
  - Verifying the Installation
  - Recommended Parameter Settings
  - Uninstalling MogDB
- Manual Installation
Administrator Guide
AI Features Guide
- Overview
- Predictor: AI Query Time Forecasting
- X-Tuner: Parameter Optimization and Diagnosis
- SQLdiag: Slow SQL Discovery
- A-Detection: Status Monitoring
- Index-advisor: Index Recommendation
- DeepSQL
- AI-Native Database (DB4AI)
Security Guide
- Database Security Management
Developer Guide
- Application Development Guide
  - Development Specifications
  - Development Based on JDBC
  - Development Based on ODBC
  - Development Based on libpq
    - Development Based on libpq
    - libpq API Reference
      - Database Connection Control Functions
        Description
        PQconnectdbParams
        PQconnectdb
        PQconninfoParse
        PQconnectStart
        PQerrorMessage
        PQsetdbLogin
        PQfinish
        PQreset
        PQstatus
      - Database Statement Execution Functions
        PQclear
        PQexec
        PQexecParams
        PQexecParamsBatch
        PQexecPrepared
        PQexecPreparedBatch
        PQfname
        PQgetvalue
        PQnfields
        PQntuples
        PQprepare
        PQresultStatus
      - Functions for Asynchronous Command Processing
        Description
        PQsendQuery
        PQsendQueryParams
        PQsendPrepare
        PQsendQueryPrepared
        PQflush
      - Functions for Canceling Queries in Progress
        PQgetCancel
        PQfreeCancel
        PQcancel
      - Example
      - Connection Characters
  - Psycopg-Based Development
  - Commissioning
  - Appendices
- Stored Procedure
- User Defined Functions
- PL/pgSQL-SQL Procedural Language
- Scheduled Jobs
  - PKG_SERVICE API
- Autonomous Transaction
- Logical Replication
  - Logical Decoding
    - Overview
    - Logical Decoding by SQL Function Interfaces
- Foreign Data Wrapper
- Materialized View
  - Materialized View Overview
  - Full Materialized View
  - Incremental Materialized View
- Resource Load Management
  - Overview
  - Resource Management Preparation
Performance Tuning Guide
Reference Guide
Common Faults and Identification Guide
- Common Fault Locating Methods
- Common Fault Locating Cases
  - Core Fault Locating
  - Permission/Session/Data Type Fault Location
  - Service/High Availability/Concurrency Fault Location
  - Table/Partition Table Fault Location
    - Table Size Does not Change After VACUUM FULL Is Executed on the Table
    - An Error Is Reported When the Table Partition Is Modified
  - File System/Disk/Memory Fault Location
  - SQL Fault Location
  - Index Fault Location
Source Code Parsing
FAQs
Glossary

PQresultStatus

Function

PQresultStatus is used to return the result status of a command.

Prototype

ExecStatusType PQresultStatus(const PGresult *res);

Parameter

Table 1 PQresultStatus parameter

Keyword	Parameter Description
res	Object pointer that contains the query result.

Return Value

PQresultStatus indicates the command execution status. The enumerated values are as follows:

PQresultStatus can return one of the following values:
PGRES_EMPTY_QUERY
The string sent to the server was empty.

PGRES_COMMAND_OK
A command that does not return data was successfully executed.

PGRES_TUPLES_OK
A query (such as SELECT or SHOW) that returns data was successfully executed.

PGRES_COPY_OUT
Copy Out (from the server) data transfer started.

PGRES_COPY_IN
Copy In (to the server) data transfer started.

PGRES_BAD_RESPONSE
The response from the server cannot be understood.

PGRES_NONFATAL_ERROR
A non-fatal error (notification or warning) occurred.

PGRES_FATAL_ERROR
A fatal error occurred.

PGRES_COPY_BOTH
Copy In/Out (to and from the server) data transfer started. This state occurs only in streaming replication.

PGRES_SINGLE_TUPLE
PGresult contains a result tuple from the current command. This state occurs in a single-row query.

Precautions

Note that the SELECT command that happens to retrieve zero rows still returns PGRES_TUPLES_OK. PGRES_COMMAND_OK is used for commands that can never return rows (such as INSERT or UPDATE, without return clauses). The result status PGRES_EMPTY_QUERY might indicate a bug in the client software.
The result status PGRES_NONFATAL_ERROR will never be returned directly by PQexec or other query execution functions. Instead, such results will be passed to the notice processor.

Example

For details, see Example.