de.ipcon.schema.generators

Class PostgreSQLCatalogInspector

java.lang.Object

de.ipcon.schema.generators.PostgreSQLCatalogInspector

public class PostgreSQLCatalogInspector
extends java.lang.Object

Inspector for querying the PostgreSQL database catalog and metadata.

This class acts as the centralized catalog reader of the schema generator. It isolates all read operations against system catalogs like pg_class, pg_attribute, and information_schema.

Architectural Benefits:

• Performance (N+1 Prevention): Pre-fetches table OIDs and constraints, caching them in the PostgreSQLMigrationContext to drastically reduce JDBC roundtrips.
• Separation of Concerns: Keeps SQL DQL (Data Query Language) logic completely separated from DDL (Data Definition Language) modification logic.
• Collision Defense: Actively guards against schema corruption caused by PostgreSQL's 63-byte identifier truncation limit (CBOSchema.SQL_IDENTIFIER_MAXLENGTH).

Constructor Summary

Constructors

Constructor and Description
PostgreSQLCatalogInspector(PostgreSQL pg, PostgreSQLMigrationContext ctx)

Method Summary

Modifier and Type	Method and Description
java.util.Map<java.lang.String,PostgreSQLColumn>	getColumnsForTable(java.lang.String tableName) Gets the columns we currently *have* in the given database table by querying JDBC metadata.
java.lang.String	getTableNameForOid(long tableOid) Resolves a PostgreSQL OID to its human-readable table name using the cached map.
java.lang.Long	getTableOidForName(java.lang.String tableName) Retrieves the OID for a specific table name from the pre-populated lookup map.
void	initNotNullConstraintInfo(java.lang.String columnName) Initializes a set of table names that have a NOT NULL constraint for a specific column.
void	initTablesMaps(boolean forceUpdate) Retrieves info about all currently existing tables from the PostgreSQL database and populates the internal lookup maps (tablesPerName and tablesPerOid).

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PostgreSQLCatalogInspector

public PostgreSQLCatalogInspector(PostgreSQL pg,
                                  PostgreSQLMigrationContext ctx)

Method Detail

initTablesMaps

public void initTablesMaps(boolean forceUpdate)

Retrieves info about all currently existing tables from the PostgreSQL database and populates the internal lookup maps (tablesPerName and tablesPerOid).

Defends against Identifier Truncation schema conflicts by throwing an exception if two tables map to the same truncated 63-character name.

Parameters:

forceUpdate - Forces a refresh of the internal cache if true.

initNotNullConstraintInfo

public void initNotNullConstraintInfo(java.lang.String columnName)

Initializes a set of table names that have a NOT NULL constraint for a specific column.

getColumnsForTable

public java.util.Map<java.lang.String,PostgreSQLColumn> getColumnsForTable(java.lang.String tableName)

Gets the columns we currently *have* in the given database table by querying JDBC metadata.

Uses isolated ResultSets to prevent conflicts with subsequent database operations.

Parameters:

tableName - The SQL table name to inspect.

Returns:

A map of existing column names to their PostgreSQL column representation.

getTableOidForName

public java.lang.Long getTableOidForName(java.lang.String tableName)

Retrieves the OID for a specific table name from the pre-populated lookup map.

Parameters:

tableName - The exact SQL table name to look up.

Returns:

The OID as a Long, or null if not found.

getTableNameForOid

public java.lang.String getTableNameForOid(long tableOid)

Resolves a PostgreSQL OID to its human-readable table name using the cached map.

Parameters:

tableOid - The PostgreSQL OID.

Returns:

The table name.